If you try automating bots to do KYC for debit cards what you'll be doing is basically looking like a money launderer and get all your accounts shut down.
The existing "credit card" infrastructure is not designed to compete with that.
Now some actors like Paypal could have come up with an HTTP 402 standard and implementation 25 years ago but they never did. I am not sure why.
On-chain transactions are still not free. x402 isn't settled in batches or rolled up anywhere AFAIK, so large volumes of tiny payments are still not cost-effective. Facilitators such as Coinbase only subsidize transactions up to a point: https://docs.cdp.coinbase.com/x402/core-concepts/facilitator
There are ways around this, but with tradeoffs.