And that's why it's unsustainable for the long run.

Imagine the following situation. You're in a cue to whatever, a car wash, and that cue is in a private area, so the owner of the property can kick you out if he decides to.
Someone comes in and says they'll pay double for the service if they can get in right now, so the owner stops you and lets him pass. You get angry because you have to wait, he paid double, the ownetr thought to himself that if he has to deal with angry mob he might as well ask more for the spot in line, so they all start to bid for spots so they can wash their cars without waiting. At some point the price gets pumped so that they pay so much for the spot that they could wash the car 10 times with that money if they'd only wait.
How long can this keep going? Eventually they'll realize how much they're overpaying or run out of money.

I'm not paying $20 to send a $50 transaction. Are you?