Perhaps what happened here is a side project grew into something larger, it's now just a project, and he fell into putting more time and effort into it without making a conscious decision due to popularity - perhaps that's when it can bite you, when you realise you don't enjoy it anymore and it's become one sided.
I think side projects should stay as small as possible unless there looks to be a real potential for both yourself personally and the rest of the world - even then failing fast feels like the best idea.