Edit: Should note people are bringing up similar issues around moderation, hate speech, etc. Potentially solution would be to operate it much like a community run forum that self moderates and provides tools to do that?
a) Not-for-Profit
b) 'Free' Speech
c) Free of 'hate'
d) Open platform/API
e) Lots of potential readers for my tweets
f) Lots of interesting content to read/follow
g) Not run by an egomaniacal tyrant/someone I disagree with
A company like Twitter might struggle to hire staff without being able to offer market salary rates and the financial equivalent of stock options.
This is something Twitter doesn't have: the ability to silence entire political agendas and categories like porn, although porn still slips through the cracks on Mastodon, so it's not a given that you won't be ambushed by it.
[0] https://www.itworldcanada.com/article/mastodon-passes-the-10...
Most of the internet only exists because it is paid for by advertisers. Users won't pay. Ok, 0.0001% will - maybe.
And what about bots and info ops? What nonprofit could deal with subtle problems like that? Neither Dorsey era or Elon era Twitter could deal with bots and info ops.
And then there's "freedom of speech", which we've seen is a very odd thing for Twitter and Parler and Gab. Who gets to define it? If you let Nazis advocate and argue, it drives away everyone else.