Thank you all for the replies.
I don't expect new features every month just for the sake of feigning activity. In fact, I hate programs that turn into bloatware for that reason.
I much prefer periodic bug fix releases that improve stability and functionality, with, as Andy says, a reasonably frequent release of new features based on user feedback.
The reason I like to buy licenses even if I don't need a paid feature is because free is not a sustainable business model. If a tool helps me save time and effort, I'm happy to pay and do my little part in supporting development. Especially a tool that is centric to my workflow.
If there are external circumstances that currently prevent on-going support/development, communication, brief as it may be, with users is a key. Uncertainty is the worst position to put users in. I'm not criticizing anyone, just stating my opinion here.
Resilio works well for me and I didn't notice any bugs in my use-case, but I'm uneasy about the lack of any apparent development/support, which I fully acknowledge might resume before long.