That's actually quite impressive, considering that Mastodon is both talked about much wider, and is easier to use.

Getting an account setup is unfortunately a challenge.

Which leads to the same issue as Bitcoin, Git and other open services - costs of managing are so high, that there's going to be monopolization in the hands of the one that can attract the most resources... and even when the financial costs aren't high(hosting Git or a mailserver on your home router/server/NAS is not expensive), the time costs start to take a toll.

There's going to be a mental barrier to these things - paying $9 per month for a managed Mastodon instance is mentally way too much. I pay for Google One, to not think about storage and mail management... and get many perks with it.

i never hear of nostr before and i use mastodon for while, and twitter debacle was critical, 200000 active users is lots of people from this type of non comercial céntric products. edit: i check few nostr people and the public is quite different between the two platforms, that doesn't invalidate what i say but explain my lack of engagement in the platform

Yeah, Nostr is quite new compared to Mastodon. The clients became usable just this year. I posted my first note on Nostr in Dec 2021 and that was literally just days after the first web client allowed posting. Mastodon has been there at least since 2016.