If users do not see a visible distinction between your app portal and Facebook, why would they pay you instead of using FB for free? Is it enough to claim privacy in order to make a sale? I really doubt it.
You could be right, but it isn't that far-fetched. Consider:
* A lot of users would be in the pennies-per-month level, charged by standard Amazon usage prices
* Owning your own data is a big deal - it's not uncommon for people to pay for backups, which would essentially be an included service
* It's not unreasonable to imagine a company of Amazon's size and competence doing a very good job of this, and including novel features that FB/IG/etc can't match
* It could also be a loss-leader to get people to own servers for other purposes, e.g. hosting a vanity domain
