Not really - many are still running it on legacy appliances like they have done for years. There's also a lot of implications of moving CSFB type functions int

Not really - many are still running it on legacy appliances like they have done for years. There's also a lot of implications of moving CSFB type functions into the IT environment due to completely different security assumptions in both worlds. That's not to say you can't do it, but the circuit switched networks are very often actual literal networks of legacy hardware that operators want to get rid of and take out of service. The cost of keeping legacy systems going is also raised due to skills shortages and limited expertise. Another reason operators will try to get rid of it if possible.