This being per-vendor is the problem. I'm never going to pay in advance to use random websites, so in e.g. news this model leads to only a few big players getting paid.

I'm even less inclined to put tens of dollars into something my agent thinks might be interesting, but I wouldn't be opposed to putting a dollar in a "browsing budget" for the day.

>I'm never going to pay in advance to use random websites

Nobody is, which is exactly why x402 will never gain widespread adoption.