well Implementation is always the tricky bit isn’t it?
It’s the sort of thing videogames are naturally better at because a computer can easily track every event that happens and progress you accordingly, kick a lot of things and get better at kicking, it’s easy because this computer is counting every single time you kick something.
Translating something like that to a tabletop setting… the easiest way is just to have a GM who has the savvy and confidence to homebrew that sort of thing into the game. so maybe the trick is to just build a system that encourages that sort of thing. offhand I’m thinking maybe something that treats what DnD calls feats more like items, most systems will have a list of example items but only the most literal-minded GMs will stick to that list exclusively.
offhand I’m thinking something similar to magic items except that they become intrinsically part of the character and can’t be easily shed or taken away and rather than looting them from monsters or chests they’re earned or unlocked by accomplishing the sort of things that are already sort of naturally occurring stories within the game. like when a player makes an incredible roll at a pivotal moment, or fails skill they should be very good at, or succeeds at a roll they really have no business even attempting. what if instead of picking it when you levelled up you gained the feat Alert by winning a spot check the rest of the party failed or, even more interestingly, by missing a spot check and paying dearly for it?
another advantage I could see from something like this is that it would encourage role playing. you can’t just level up and take burglar if you want to be a clever thief, you need to get in there and start stealing things until you pull off a good enough heist to earn burglar.