Average lifespan of a (Lenovo) laptop PC?

Lenovo is a one of the biggest pc brands in the world, with a lot of customers both consumers and companies so assuming you look after your gear it should last quite a long time!

In all seriousness though, any unique hardware/design's normal lifespan is unknown because it is only after the years and years of use when you can expect to be able to measure it all and make an average. Your laptop should last a long time, wether you would want to keep it until it breaks is up to you as 2060 is almost certainly gonna be holding you back in games right now and perhaps future releases won't even be able to run on it...

So far I've never had any issues with Lenovo Laptops, even with those I used over 10 years. But of course it depends on how much you stress your system. 
In your case, cleaning your system and perhaps reinstalling Windows might help a bit.

In the commercial world its typical for a Laptop to last 3 years, though this rule of thumb may have changed. At a push you can get 5 years out of it but as you've pointed out technology moves fast. when you have the providers releasing new iterations of their products every year you will see a gap between the generations. 

One way I make a decision is does the PC play the games I want to play form the current generation at a reliable and decent performance level. If its struggling then its time to budget and save for a new one. 

You hit the nail on the head with the answer varying a lot between users and their usage scenarios. However even if you treat a laptop with the utmost care, hardware can invariably fail which is where warranty care comes into play. My Legion 7 2021 which is also discontinued already lasted just 2 under years before a catastrophic logic fault with the system board or the CPU soldered to it resulted in them replacing that very expensive component. So I'm hoping that like the engineer who fitted it said it was just a one off random failure he'd not seen before and the rest of the laptop lasts a good 3 more years since I gave it to a family member.

The more common points of failure are the screen, hinges and keyboard or trackpad apparently in Legions. However, that doesn't factor in the thermal material also needing occasional attention (the frequency of which also depending on how hard the laptop is pushed or if there's sufficient airflow even if it's not been thrashed within an inch of it's life)

GPU longevity is a tricky one, with the advent of DLSS and competing RSR technologies being utilised you could argue that anything RTX will now last a bit longer but it really depends on the level of VRAM and how game developers make use of the new code options available to them. Starfield for example was developed by Bethesda with an AMD partnership deal, so DLSS being added after launch both unofficially via a user mod and later officially was only to be expected.

Console ports is another notorious area of modern games releases that taxes even the highest configuration PCs.

So I would say be sensible about what you use the laptop for and basically have realistic expectations, because the hardware itself can physically last a good 5-7 years even if you can't by that point expect to play the biggest games of the year apart from on lowest settings at 30-60fps which for a lot of genres isn't an issue with the exception of competitive combat/FPS or racing SIMs.

You can even extend the life of the hardware should it no longer be supported for Windows by using Linux. Laptop support with Linux is partly reliant on manufacturers and the user community alike with a lot of reverse code engineering going on. Lenovo are fairly good though submitting firmware and code to the opensource projects as a kernel partner for a large percentage of the components shared across their thinkpad, ideapad and legion range. there are of course exceptions like windows specific audio codecs that require pre-amplification which is why sound can be a lot weaker out of the box on linux until you find your way around the audio mixer to boost it via the equalisers manually. The other main areas are fingerprint scanners and wireless chips, although PCIe wireless card support has improved vastly (it's the USB adaptors that are still more troublesome)

TLDR - be realistic and you can get about 5-7 years from a consumer grade Lenovo laptop

In the gaming world three years is a long time, especially the last three years that we're seeing big changes on the way games are made because of the console generational change, new technologies and companies not putting in the development time for proper optimization, a 2060 mobile gpu having problems in 2023 games is to be expected. Actually it doesn't matter if its mobile or not, after 3 years its normal for all cards to start lowering settings if you want the same FPS as you had when you first bought it, that's just how it goes unfortunately, 2023 games will be heavier than 2020 games. My advice, if strictly for gaming, is to switch platform if possible, consoles don't have this issue because games adapt to their level and they last for about 7-8 years, desktop is easily upgradable (but costly).

Interesting; thanks for sharing that. I'll probably push this laptop for another 1.5 years, but I'm just a bit disappointed to see how quickly it deteriorated, and especially how much it freezes up and skips while I'm gaming. Perhaps I need to give it a good cleaning and see if that makes a difference, but right now I'm sure I won't get 7 years from it.

I actually had a post on this forum about conversion to consoles, but realistically, I don't think it will happen for me. Although I think you're right about how quickly things change, I prefer the flexibility of PCs and the types of games that they offer that consoles really can't do very well (I'm thinking RTS and grand strategy), so although I'm not entirely happy about always having to consider an upgrade to play the latest games, I'll stick with PCs for now.

10 years is impressive! You must take really good care of your systems 

It really depends both on the specs of the laptop and on what you want to do with it. If you want to play the newest and most demanding AAA titles with very high quality settings, you'll have to upgrade a lot. If you play CS:GO all the time, you can probably still use a 10 year old gaming laptop.

PS. You can try to see if you can clean the laptop if it is working so poorly. The fans may be clogged with dust.

Your laptop is not dead yet, but might need to run games on lower graphics settings then you might want to. I am not even going to talk about my laptop specs, because it is over 7 years. 

When I buy a laptop I normally go for the gaming version because of the better cooling and that I like to push my gaming gear in long gaming sessions.

But is also depends how it is used, my parents laptops lasts a lot longer then mine, because they just use them as home office laptops and do not game a lot.