I'd have to assume that in circumstances where PS5s are easily available, it had to do with overestimating the demand in that particular area. I live in major city and you can find usually find the disc based PS5s at the usual places (BB, GS). I have never seen the digital only one in stock. But based on what I read online, this is obviously not the case throughout the country.
Our Best Buys usually have them because they basically hide everything videogame related, so you only really would know if they're in stock if you ask or peak at the gated off section where they keep consoles. I'm guessing that plays a role in it.
... also, $500.00 for a date !? Just why?