I like FOSS not being mainstream because it takes a special type of personality to break with standard convention and make the extra effort to learn about FOSS. This weeds out a lot of people that would otherwise turn FOSS into Facebook or Instagram. Remember how Reddit used to be ~12 years ago? Look at it now. While it's not entirely mainstream, the general population has at least heard about it, and it's slowly become the crap it is today.

I'm happy Lemmy isn't mainstream. We do miss out on some benefits of dependent on a large user base, such as specific niches, but at the same time, we have a respectful community that mostly adheres to solid values and ethical standards. People here are building a supportive community.

That wasn't my experience with Reddit for about the last 5 years. It became an idea popularity contest, where the same repeated joke was the top comment and dissenting voices were buried under a sea of downvotes. Discussions were about who was right rather than what idea made better sense for the topic. While Lemmy still has remnants of that stemming from the recent migration, but it is nowhere near to Reddit's level.

Coincidentally, I was already on my way out of Reddit when the API fiasco happened and got lucky enough to hear about Lemmy before I completely left. I'm never going back to Reddit, just like I'm never going back to FB and IG. Hopefully, if Lemmy starts becoming mainstream and the culture changes, the ability for instances to defederate will be helpful at maintaining the community-feel of this place.