Many Blockstack apps are about managing user data. If you want to make profit from this data then you stay where we are at the moment with data capitalism...

You need money to build and run the apps. Source: I do this for a living.

The operational costs are considerably lower with Blockstack, since the app doesn't host any user state (and in many cases, no state at all). Most apps don't need a database of any kind -- all the business logic runs client-side in the user's web browser.

Event if operational costs going to be 0, it's not a viable business model to not have profit.

I never claimed otherwise ;)

However, I will claim that the lower operational expenditure (and lower liability for holding user data) makes profitability on-the-whole easier to achieve in Blockstack-powered apps.