Because i struggle to imagine the ads i watch would amount to $15/m. So it feels like significant markup.
A flat rate seems either upcharging, or subsidizing. Neither feel good as a consumer.
I rather (and have) quit than pay them $15/m for a handful of ads. They started fighting a month back or w/e and i just stopped watching them for ~2 weeks. When i tried later, the "problem" was gone lol. Not sure what happened.
I'd much rather pay for a platform that gives money to creators more directly. I pay for a fair share of things on Patreon, for example.
edit: I should note, my assumptions on price are based on how little ad views net in value.