You can't really send an email without approval either - Either you pay for service with money, or you pay with your identity (usually your phone number), or you get a dodgy shit-tier provider like lolcow.email that can go down at any time and probably delivers straight to spam.
You can send spam on day 1, but you're probably limited to like 300 emails per hour and if you're banned for being a spammer, you only have so many phone numbers/IP Addresses/dollars you can use to create disposable addresses on reputable email providers.
You could set up your own email server to make infinite accounts, but if you don't have a clean IP and clean domain and all the necessary DNS configs then your outgoing won't go anywhere.
I often read that you shouldn't self host your own email because it's a pain making sure every possible normie email provider will accept your emails, and it's not worth your time. Once I saw a discussion about how those people lied, it's easy to self-hosted your email! ... As long as you pay someone else to handle outgoing messages. And then they pondered how much of the system needs to be under your own control in order to qualify as self-hosted.
Legend has it,
Microsoft detects their own emails as spam.
The problem with spammers is they have so many more opportunities than malicious browser downloads. They send so much junk that even if the majority of it filtered out, they'll get some messages into people's inboxes. And the average person opens more emails more often than they install software. Even a success rate of a percent of a percent of a percent would be a lot of suckers.
