good question. I think the community fell off and many plugins were left unmaintained. I was using it for over a decade up until recently. ST4 had so many plugin issues and it stopped being worth manually fixing.
For me, it was that the maintainer of a language plugin I used was, um, challenging to work with. I wanted to contribute to add some much-requested functionality and he talked to me like I was a toddler and warned me not to waste his time.
