My only thought is that it is exhausting, and can end up being a distraction (think of hosting a never-ending telethon), having to constantly ask for financial support for something that is delivering real value but being given away for free.
Discussion
I get that, V4V hasn't really been tried outside of content creators (podcasters, musicians, writers etc..) but I would still recommend checking out the value4value.info site and maybe you can pick up some tips and tricks from it.
I only chimed in on the first post because paywalls aren't "V4V" but the community aspect of the SeedSigner project has the V4V spirit if that makes sense.