[fragmede]

Sell private domains as an "enterprise" feature, and have different sets of IP blocks warmed and ready to go for when they eventually get blacklisted. But selling it as a service involves a higher level of effort due to that exposure. Configuring a private domain for just yourself to solve the problem just for you doesn't have the same risk exposure.

mailinator's been around providing this (as a recieve only) service for decades by this point.