Have you ever been in sales?

If the requests are real there would never be 5 thousands, let alone 5 millions (or the vendor would count their lucky stars).

If they are spams that already happens today as well, at scale. AI bot would not change that.

The vendor will never blindly make a sample just based on a single request. There will be back and forth. Maybe require proof that the inquirer is serious.

Sending out RFP to 40 vendors isn't unusual.