Well, then give me self-signup with a clearly outlined verification flow that I can follow from A to Z.

If you give me a form where I can upload my passport or enter a random number from a charge on my card, that counts as "instant" enough. On the other hand, if you really need to make me wait several days while you manually review my info, fine, just tell me upfront so I can stop wasting my time. And be consistent in your UI as to whether I'm verified yet. It's all about managing expectations.

Besides, Amazon hands out reasonable quotas to newly created accounts without much hassle, and they seem to be doing okay. I won't believe for a second that trillion-dollar companies like Google don't know how to keep abuse at a manageable level without making people run in circles.