Something that I was thinking of yesterday when I was wondering why the only streaming service with an app was that awful HBO Max one: The iOS user base is HUGE. The Mac user base is a fraction of a fraction of that, and the number of people on the new M1s are a fraction of that.
There really isn't a huge incentive at this point for a company to devote dev resources to it, even if it is "simpler that ever before".
Once you build that app you have to have a team to support it and you have to test against new versions of MacOS and there are costs incurred with that, and as of right now, I am guessing that a lot of companies don't feel a lot of urgency there.
Maybe that occurs later as the Mac silicon user base increases. Or maybe it never happens because Netflix doesn't see the benefit to create and support a new app for the very comparatively small Mac user base.
It's actually the same type of reasoning hackers use. If you only have a finite set of time and resources to complete a project, you are going to focus on the project that has the biggest potential for gains. Since Windows/Android/iOS all have significantly larger install bases than the Mac, developers are going to focus on those groups, especially if the app provides a revenue stream for the developers. Likewise, the overall userbases for those other OSes are more likely to game (even if it's just playing Solitaire or Candy Crush) than the typical Mac OS user, although that may change over time as the M1 gains ground in the marketplace.