It's not just Mac software - desktop software in general seems to be stagnating.
As noted, several app categories seem to have "matured" and/or ossified and are dominated by one or two players. For example, Microsoft and Apple dominate the "office" productivity software market on macOS.
Moreover, apps like Discord, Teams, VS Code, etc. seem to be cross-platform web apps which are clunky and unsatisfying compared to native apps. (Other web apps don't even have desktop versions and only exist in the browser.)
That being said, Adobe's offerings are expensive subscriptions which have opened up a market for Affinity as well as Pixelmator and Acorn.
As noted, several app categories seem to have "matured" and/or ossified and are dominated by one or two players. For example, Microsoft and Apple dominate the "office" productivity software market on macOS.
Moreover, apps like Discord, Teams, VS Code, etc. seem to be cross-platform web apps which are clunky and unsatisfying compared to native apps. (Other web apps don't even have desktop versions and only exist in the browser.)
That being said, Adobe's offerings are expensive subscriptions which have opened up a market for Affinity as well as Pixelmator and Acorn.