This. This is the vision I've understood that Steem is going to be. It is complicated now, because we are on the developing phase of it. Onboarding will become easier. I think 3speak already uses a model where they "rent" a Steem account, so they have the custody of it, but once an account starts accumulating wealth (STEEM) the user has an option to take full control over the account. And starting to use 3speak is as simple as using email, Facebook or Twitter account.

Steem is the electricity that powers it all. Those people that own some Steem, will have an ownership of a small piece of that network. Like you said, eventually new people won't even know what Steem is. Maybe it works out, maybe it doesn't, but I'm willing to take the chance. But the existence of Steem Engine is already a step to that direction. 

The greatest gains come when there's a great risk and uncertainty. It'll be a great ride – has already been – no matter which way it ends :)