Vast majority of people claims that CPU is the most important part responsible for higher framerate in cs:go. While it is true for lower resolutions (below 1080p), starting with 1080p (some good pro players including Ropz use 1080p) and up GPU starts playing higher and higher role. Here is a benchmark video of difference within 4 cards of 1000 series (1070, 1070 ti, 1080, 1080 ti) in 1440p.
As you can see, upgrade from 1070 to 1080 ti is a big deal, adding whole lot 100 fps (in said benchmark).
do you know what 'the vast majority' means? We are talking about millions of players then you name 41 PRO players... The vast majority claims CSGO is CPU bound... and they are right if you use a lower resolution.
I use 1440p then I must have a good GPU.
I am not saying that people don't use native resolution I am just telling you why the vast majority claims the game is CPU bound.
DO WE WANT ME TO DRAW?
For those who do not use native resolutions upgrading GPU is not a huge deal for he vast majority
For CSGO the CPU still is the most important thing, with good CPU and bad GPU you can run the game better than with a bad CPU with good GPU. GPU starts to matter a bit more if you turn up quality settings like AA and if you crank the resolution