The real problem is Amazon having monopoly. If there were some true competition, I couldn't care less about Amazon closing my account as I could go to a competitor.
If there was more competition or these things were based on open standards you could easily switch over I might be more inclined to agree, but I think right now these companies have way way too much power.
The threat of a company deleting an account for many people would be detrimental to their lives. We are way way too dependent on corporations and in kind of tired of people being scared to regulate.
Regulation often makes things worse, so we can't just look at the potential benefits without considering the potential (and likely) negative consequences.
That doesn't mean folks are scared of regulation. It means they're _smart_ about it.