And you can't use many from those services to actually register an account for a meaningful service. E.g. have you created Instagram account with them?
Seems like there is a determined will to blacklist as many as possible.
I believe you're thinking phone numbers from legitimate VoIP services like Twilio, or the "texting app" service-providers that build on top of them.
The GP is talking more about phone numbers from purpose-built (usually Russian) "secondary market for other people's credentials" marketplaces, where people sell the use of their own personal phone numbers (usually through cloud remote-control software they run on an old Android device with the SIM in it.)
