Clients should implement Charity 2.0 - splits availability for zaps.
Most users would then happily defer some % of their incoming zaps to devs, charities, etc.
Discussion
I think clients should take a few % off zaps and work as a for profit company. A bunch of for profit companies and contribute to protocol development. This is how most standard bodies works - IEEE, IETF, ITU, W3C, etc
For profit but not necessarily need to be a ‘registered corporation’ tho.