I don't think it's all that complex to build a decentralized advertising system. Voice is attempting to do something similar. I have no faith in their execution, but the concept is sound. BAT has been doing pretty well, though again, a lot of development ahead.

Like with advertising, obviously you can't shoehorn tipping into the current system, it obviously won't work for the reasons you point out. I mean a complete overhaul of the system where there's no longer inflation-funding or a common reward pool. But more on that later.