Gaming is highly constrained by memory bandwidth in the general case. It scales with things like resolution, framerate, and number of textures.

But of course in practice it depends on the details of what you're doing. This is why I acknowledged up front that it depends on what is meant by "really good". I think iGPUs are sufficient for a huge number of titles in the exact same way that an entry level dGPU from 2018 also is. But I don't think most people would consider that "really good" as you'll generally be stuck in the ballpark of 1080@60 and don't even think about photorealistic VR.

I think it's interesting to note that a while back GPU horsepower reached a point similar to that of CPU horsepower and system RAM capacity that's "good enough" for most common tasks. You don't need (and presumable never will) 32 cores or 64 GB of RAM to check your email or watch youtube. Similarly 1080@60 is sufficient to enjoy most game concepts.

Yeah I totally agree with what you’re saying. Basically, that “good enough”-ness for my use case does involve things like not playing photorealistic VR and very much accepting 1080p render resolutions or sometimes even lower (thanks, XeSS/FSR/DLSS!)

The main point with it is that it’s not a matter of “oh I can’t play the games I want to play reasonably” and that is very much not how integrated graphics used to be.