I think subscriptions will be terrible for vendors in the end as well.
First, because they have to compete with the likes of Office 365, which offers an Office Suite, 1TB cloud storage, and 60 Skype minutes (at least the used to) for little over 5 Euro per month. Subscriptions for more basic programs will look overpriced in comparison.
Second, as subscriptions become the new normal, we will see services like Apple Arcade. I think Apple Arcade will eventually eat up a lot of revenue as casual gamers will move from purchasing games to the 'all you can eat' Arcade. If Apple Arcade turns out to be successful, what holds them from launching 'App Arcade' [1]? Vendors that don't get into the App Arcade will lose a lot of revenue, vendors that do get into App Arcade will have a steady source of income, but will also be completely at the mercy of Apple (or Microsoft).
[1] I know there is SetApp, but anything that Apple launches has a lot more visibility. They also have more clout to get high profile applications in such a service.