> It's not just Mac software - desktop software in general seems to be stagnating.
Well... the golden ages (which I'd say are the mid-90s to 2010-ish) are over.
- Business software has pretty much consolidated and the existing tooling from office suites to data warehouse and workflow stuff (i.e. SAP) offers so many options that it's incredibly hard for new players to gain a foothold - you need to identify some niche, build it out well enough to offer an actual benefit and market the hell out of your idea, and maybe in 0.1% you have a chance at lucking out.
- there are a bit of open-source efforts (e.g. Thunderbird, Mozilla, LibreOffice) but they lack funding so they struggle along, mostly used by those not wanting to spend money on the above-mentioned pay products
- Utilities from file management (Winrar, Winzip, Total Commander) over media players (Winamp) to task managers have been absorbed by the operating systems. These days, particularly Apple is known for outright ripping off ideas from popular App Store apps.
- the people who made the really innovative apps in the golden age were highschool and college students. These people have since found employment at big companies, removing both the time and the ability to work on side gigs (hard to do a side gig when you're staring at a screen for 40+ hours a week, and why bother with side gigs when your employer demands copyright even over stuff you do on your own time?). Today's young people aren't interested in programming any more, they're more interested in Tiktok or to fight on the political level.
- All major OS platforms have alienated developers. Microsoft with win32 -> .net/WPF -> UWP -> WTF, Apple with Cocoa -> WTF, and Linux never got around to settle on one way of packaging applications and dependencies or on window managers or on <insert long list of forks, disagreements and other crap that happens without a central steward here>.
- it seems like the flurry of cheap or free high-quality IDEs and the consolidation (basically it's VS Code, IntelliJ or Eclipse these days) directly coincided with the end of big-corporate desktop app developments. Basically when no one pays four figures for an IDE any more because no one wants to develop for desktop, it makes sense that the others go down in price (Visual Studio/VS Code) or vanish (Borland).
- Mobile, web-based SaaS and subscription based stuff lured a part of said alienated developers with better pay and actual innovation
- ETA: Games... that's a different beast. Can't argue that there is innovation present. But most of the attention of the major actors seems to be focused on console-exclusive or other walled-garden deals, and the mobile market draws in the f2p whales. There are rare gems (e.g. Factorio) that simply would not work on a console due to a lack of a keyboard, but that's it.