Weren't 512GB models selling like hot cakes to the complete surprise of Apple? Wait time was up to 3 months last time I checked. Glad I got mine last October.
“Like hot cakes” is relative.
> The 512GB Mac Studio was not a mass-market machine—adding that much RAM also required springing for the most expensive M3 Ultra model, which brought the system’s price to a whopping $9,499.
Number of people willing the number of people willing to spend $10,000 on a computer is pretty tiny. Maybe they are common enough in HN circles, but I doubt any one at Apple is losing sleep over them.
Any custom configuration takes a while for them to prepare. I remember my M3 max took 2 or 3 months to a arrive.
Good thing is they only seem to charge when device ships so if an M5 comes along you should be able to cancel the m3 ultra and get the m5.