You don't get it, it's about the relative proportion. Let's say 1% of steam users have a 2080, that doesn't mean the relevant market for higher-end GPUs is 100% of the Steam market. The AAA market is a smaller SUB-SET of the wider steam market. Just like how steam market is a small sub-set of the wider PC market. Which is yet a smaller sub-set of wider computer market (PC+Laptop+mac+etc). Just like it doesn't make sense to think about how many people don't have a 2080 that only use their PC to edit photos, likewise it makes no sense to think about how many DotA2 gamers don't have a 2080 - they're not the relevant demographic!
And h/w surveys are done at random, you can't decide to take it. Hence so many 768p laptops and various old cards thanks to Chinese internet cafes.
Your PC is already basically a Series S equivalent almost. Ideally you'd want a new GPU for DX12_2 features and for 4K, but if you go 1440p 144hz then you'll want to think about at least a Ryzen 3600 also. You're gucci otherwise.