collaboration is a good thing if you have the team work skills and need to fuse your skills together.
However, the reason why I've moved away from commercial games is I enjoy independence of not having other developers relying on me (or me on them.) I like sharing my time with many different things from programming to artwork to marketing. Sticking to tighter time schedules is less risk. Working with developers who are located in different cities (or countries) has also been quite problematic at times. Above all, I love the way all the money that comes in belongs to me, hehe
I wouldn't consider any future team work myself unless it was with a small group located close together so we could have plenty of business meetings in the pub
I know not all Indie developers are focused on solo development but I find it works for me.