“These entities are now selling off (if they can) these blocks at prices 10,000+ USD per /24!”
240.0.0.0/4 holds 524,288 /24s and has sat reserved since 1989 for a type of routing nobody invented. AWS already uses it internally. Every version of Windows refuses it, and so do FreeBSD and NetBSD. Early networks that grabbed 256 /24s in the 2000s now get the payday while everyone else pays rent on CGNAT.