Farnell UK has 18,230 Raspberry Pi 3Bs in stock. Between Farnell and RS most of the boards are available in many hundreds within a few days.
Edit: Looks like Farnell UK doesn't sell the Zero or Zero W, and any store that does is limiting themselves to 1 per customer.
It might be different in other countries, but I have to imagine that anyone in the US could get their hands on a Zero if they wanted one.
A zero, sure. But I want like 20, haha. Unfortunately my nearest Microcenter is 600 miles away. If I can't get 20 for $100, they're not really $5 each.
1 at $5.00 each, 2-5 at $9.99 each, 6+ at $12.99 each