Expectations have increased in multiple dimensions.
1 - Users have been trained by Apple and Google to expect endless upgrades for $2. When I grew up, Eudora, an email client, retailed for $100-ish, with an incremental $50 for ugprades every couple years. You can make a living on the latter pricing, but require hugely popular software for the former.
1a - as software has moved to mobile devices and web, the OS updates more often. ios does annual releases, android does the same, and chrome has a 6-week-ish update cycle. There's simply more thrashing, and it's no longer good enough to ship to a copy of Windows that updates every 4 years.
2 - There is a lot less end-user only software that just runs on a users device. It's far more common for software to require running servers to provide part of the service, and/or to code against apis that regularly change and require ongoing updates.
I'm aware no eng is owed a living, but if they can't make a living, the software becomes unavailable: either not written or not maintained.
see eg Sketch's rationale for not building an ipad app.
https://www.designernews.co/comments/173706 quoted in case the link disappears:
> We don't have plans for an iPad pro version at the moment. Yes, it has a beautiful screen, but there's more to consider, such as how to adapt the UI for touch without compromising the experience.
>But the biggest problem is the platform. Apps on iOS sell for unsustainably low prices due to the lack of trials. We cannot port Sketch to the iPad if we have no reasonable expectation of earning back on our investment. Maintaining an application on two different platforms and provide one of them for a 10th of it's value won't work, and iPad volumes are low enough to disqualify the "make it up in volume" argument.