That's how technology works. It only makes sense that a modern Mac is more capable than one from 5 years ago. The same way a modern Nvidia GPU is more capable than one from 5 years ago. But it needs to be utilized and that's where the problem is.
Take Path of Exile as an example, a game I've probably played most over the past few years because it's strategic, fun and can be played with friends online, be it for 10 minutes or 10 hours.
Now, one has to understand that PoE, despite being free, really isn't free. In order to really play it past the tutorial (Acts 1-10), one needs to pay about $100+ for stash tabs to make it playable at all as it's based on farming and crafting. The further you get through early, mid and late game, the worse this gets and if one is not playing SSF, stash tabs need to be bought to store gear for trade. While GGG are adding stuff league after league, they eventually decided to develop a DLC. When they realised that all the stash tabs (and skins) players already bought would be usable, they pushed that new DLC into a new game, PoE2. That way, they can sell stash tabs (and skins) again. And because they keep expanding leagues, large chunk of PoE is already running with the PoE2 engine, otherwise they could not have made the league changes. In order to not cut off Mac players the same way Valve did with CS, they had to port the engine over. That allows Mac players to keep playing PoE1 and also PoE2, which was never supposed to happen and only did, because they needed the update for PoE1.
Now the problem with this is, PoE is in the worst state it has ever been. Go beyond the tutorial and the game is pretty much unplayable with dips to 1 or 2 FPS. Impossible to get a Deadeye Lightning Arrow to level 90, because it's based on evasion and movement. It's better for a Archmage Ball Lightning Hierophant, because it's way more tanky and dropped frames don't lead to death. But it's absolutely no fun to play at such low frame rates and even switching gear in town has massive FPS drops. You really need to go to your hideout for equipment changes.
So even with the most capable hardware in Macs ever, in case of PoE isn't never performed worse. Granted, it's not a top performer on Windows either. But at least there's the option to just upgrade to a more powerful GPU. One can't upgrade to a M10 Max it would probably need to run this smoothly. And while that isn't the rule for all games, more care in form of optimization is needed from developers. And that's back to the initial situation, all the way back to the 90s and as you say... number of people playing games on Macs needs to go up massively. Chicken and egg problem.