I'm sure you had the best intentions, but this comes off as "well you should have been more active. get good.". It's not helpful, and can come off as rude and presumptuous.

One site my sentiment was about was one where most events were just me and the other admin participating, for example. We were active, but, for whatever reason, the premise didn't resonate with other people. A lot of work goes into being an admin, and if that work doesn't result in engagement it's human to start feeling like the costs outweigh the rewards. There's a point where you just have to accept that and move on, and for me that's when a site starts to feel like it's essentially a public 1x1.

I also want to stress that the way I view it is: It's disappointing, and a little sad, but I don't regret it. I'd rather try and fail over not trying and not getting to experience what fun I had while it lasted. Hobbies can be ephemeral and that's okay.

Ouroboros of "the site failed because of lost interest" to "interest was lost because of lack off members" to "new members didn't join because of lack of interest" and rinse and repeat. I really wish a handful of members was enough, because we had some great members, but it makes it that much more impactful when one or two members becomes inactive and it's just a domino effect from there.