I mean short and long term there’s pros and cons to that. however there’s a reason why that started to fall appart with e-mail. In short if it gets popular, than hosting servers with no throttling or post limits means spammers are going to go crazy, and rather than play the never ending unwinnable whack a mole game as bad actors create thousands of instances a day, hosts of any instances worth targetting will have to do a “instances are assumed malicious until proven benign”, (IE a whitelist method)

Well that’s also where fediverse is a perk. There are, and likely will always be parallel channels on different instances. IE so while lemmy.ml may have the largest asklemmy, there probably will be smaller less active asklemmy’s on other instances.