This is a very good list by @davidslifka. I'd propose that the goal isn't to scale -- we see what mass media's and venture capital's expectations have done to the internet -- but to succeed, with many definitions of success. David explores a number of needs, includilng onboarding, hosting, moderation, and media coverage of the fediverse.
https://medium.com/@davidslifka_86286/what-the-mastodon-ecosystem-needs-to-scale-cb845f30cfe8