Yeah… but I think it’s too late for Mastodon to be popular. Bluesky is already at the tipping point.
Mastodon just needed to sign you up to their own default server, power users could sign up to different ones and they would have still got the regulars in the door. Mastodon also needed twitter feature parity, something Bluesky also managed much faster.
Once people are in and settled, then they would start asking questions about that URL after their username, people would slowly become comfortable with the federation and understand it.
It’s not the price that is the problem, it’s how iCloud is integrated into the device, in a way Apple don’t allow other cloud services to do. iCloud has access other apps simply do not, so they cannot compete fairly.