Look let me give you a PC enthusiast example (I'm one so partly telling my troubles).
If you have an amazing GPU like a GTX 980Ti, but you only have those stupid old Bulldozer FX 8350 CPUs, and on top of that a goddamn HDD => You are not gettin everting out of your GPU, not even close, not even let's sat 30% of it's PEAK power.
Now put in an i7 CPU (of course whole DDR4 and MoBo, whole shebang), but can't afford a good SSD yet => You are getting somewhere, suddenly you jumped to 75-80% of using your GPU at its PEAK power, only those frame times are terrible, 1% of frames are lagging like hell.
Now finally can afford an m2 SSD, put that in even Windows boots in seconds, but forget that, load the game in seconds and you are now at 98-99% of PEAK power of your GPU, frame times are amazing, it is now finally capped at 60fps only perhaps a few hiccups. Why 1-2% missing, cause it's PC there is always better CPU, GPU and SSD, etc. Why hiccups, well everything from bad drivers, to background updates, to game bar acting up, to even game engine not being optimized can be the goddamn reason.
I'm a PC gamer. Don't try to fuck with me on this topic, I know what I'm saying when I'm saying that sometimes SSDs do compensate for CPU/GPU combos, more so if those are also powerful but bottlenecked by I/O, less so when they're weaker and bottlenecks are all around. I/O on HDD for the games coming out since 2016s is THE bottleneck period. Solving that bottleneck doesn't magically make your GTX 760 into GTX 980TI, but if that top GPU isn't hitting anywhere near it's peak perf then solving any bottleneck I/O included will give you more FPS.
School is out.