Yeah, I feel that. Although the salesforce acquisition was way back in 2010, I think heroku still had some innovation and progress after that for a few years. But not in a few years now.
The good news is that heroku started out so solid that it can last a while in this state still being a good product. But it doesn't seem great.
I still don't know of anything else as good as heroku for "we don't really have any ops expertise in-house, do it for us and make it Just Work". I doubt the OP is that. I really don't have time (or honestly interest) to learn kubernetes.