"Wouldn't it be better for all parties if they just focused on maintaining the best possible version of their core offering at the lowest cost?"

Yes, absolutely.

There is value in new features and functionality but there can be so much more value in a predictable, stable tool that can be depended on and returned to.

There are people who cancelled their first account with us before dropbox existed and have returned, post-covid, to find a familiar tool to be picked right back up again.

This has been immensely valuable to a great many people and we wouldn't dream of ever changing it.