I feel like the demand is filled thoroughly enough that current Crypto owners are chomping at the bit waiting for spare uppers to be released; there's grifters on "the other site" selling BNIB Cryptos for above retail, which should be the sign for the demand being clearly satisfied by end-users.
Retailers have them fly off shelves because it's basically the only 5.56 semiauto option left, anyone who's filled their void by getting a Crypto probably wants spare uppers available sooner rather than later.
I for one would love to see a .308 Crypto or even have a purpose built 7.62x39 upper assembly available, more likely to see the former than the latter with how things are progressing, but I can dream on.