If you think anybody will be willing to secure the network without direct incentive especially after Bitcoin introduced mining incentive, you are in delusion.
I think you are very incorrect with this thinking - currently people spend "hours every day" creating content on Facebook or other such things for *zero profit*. Why on earth would they do that?
If you can simply get those people to run a (presumably low-power requirement) node then you will be able to secure a blockchain without needing block rewards at all (effectively it is your cost to be a part of a social network).
From what i can gather it's even simpler than that. They'll need to contribute to securing the network in order to send a transaction.