Well, I would believe the Star Citizen guys, they have a history of developing games that run "smooth" for hardware that doesn't even exist yet (Wing/Strike Commander).
Otherwise, I'd say no. I've never heard that complain from anyone I ever talked to in game studios. Journalists, reviewers, YouTubers, etc. sure... but they don't create games.
I'm a little lost. Are you a game studio or is this based on your opinion as a gamer?
I asked because I thought some game studio complained about performance in Macs and that was (one of) their reasons not to port.
I assume you mean we have ~2-3% of people playing games on Macs. And somehow we're jumping to the conclusion that's because only ~2-3% of Macs sold are capable of playing games, which is wrong. You can play games on Macs with iGPU... actually have been able to for many years (+ low end GPU systems like Intel iMacs). Sure, not every title, not at max settings, but it works. Looking at ~2-3% of Mac gamers, you have about 3x that on PC, people playing with Intel iGPUs, not counting AMD counterparts or old/cheap GPUs like 600/700 series Nvidia, MX150, etc. or AMD equivalent, those come on top to the 3x iGPU gamers.
Most Macs are simply used for "work", as are most company PCs. The users have no intension to play games.
I don't really have to put myself in the shoes. I agree it makes no sense, not even because of the market share, but because of the effort you have to put in a macOS port. I have abandoned all my Unity and Unreal based projects for macOS this year due to the amount of work it requires to port to macOS. Most still work on Linux with way less effort, but the graphically intensive stuff is Windows only, because it's just not worth investing the time it requires to port. 2021 is the year I gave up on macOS and Linux ports for everything... a sad year.
For the gaming industry I have my doubts it will be different. For smaller indie games, sure. But for really polished AAA titles? Those are usually DX12 now and might offer backward compatibility with DX11 (those still run via parallels/crossover). DX11 support will become less and less common and most DX12 titles are developed with resource binding tier 3 in mind, which is more than Metal/macOS (as well as MoltenVK) can handle (on purpose). So porting games will become more difficult from DX12 to Metal than DX11 to Metal.