I agree with the main gist of the case you're making, but unfortunately with this part:
Account setup only takes a second and then after a short approval period you’re ready to go.
in practice it doesn't always line up with the theory. When I created my account it was relatively straightforward like you describe, but I've tried to convince some acquaintances to create accounts and for some of them it has taken weeks to get approval. The powers that be say they're working on it, which is good, but when a delay does happen it tends to undermine people's interest in trying the platform.
Yeah. It's important to realize signing up new users costs money. I believe Steemit Inc is delegating new users with $10 US+ in STEEM power. Also you do not need to sign up through steemit.com. There are sites that let you pay for yourself and then there is no delay.
Yeah, hopefully they will find a way to speed account approval up soon. On the plus side, I understand their procedures help fight against spammers which improves the network and the ability to earn for all us genuine users!