The thing is, I don't understand if V4V is such a bad idea, doesn't work, and will collapse, why does everyone spend so much time talking about how it won't work as a payment model? Surely you would just not bother because the people implementing it would just not do it anymore. 

The thing about decentralized systems is the modularity with which they are build allow for different models to be tested. The reason why paywalls and V4V are clashing is that one hurts the other and people advocating for either are just partisans. If there's a paywall, V4V gives away content for an ostensibly cheaper price. If there's a V4V model pay walls give people FOMO and draw from charitable payments. You are participating in a culture war. 

 I don’t think V4V on its own has an incentive structure that drives behavior. The cases where it does work are zap.streams that put the top person on the leaderboard or give mention to the person who contributes. If zapping were completely anonymous, it would be exceptionally rare. 

 But it isn't completely anonymous... If my grandmother had wheels she would be a bike. Again, I don't understand the aversion beside standing athwart the hill of payment schemes yelling "Stop giving money to each I other all willy-nilly!" 
Saying it has no incentives then listing incentives is definitely a new way to make a point.