While the reasons you list reduce the cost to ABC for cancelling Kimmel, it is no less outrageous and alarming that the current administration forced Kimmel out because of his criticism of the government.

Maher, like the Dixie Chicks and Garofalo, criticized a deeply popular war (regardless of what you think of it) and were ostensibly cancelled pre-cancellation era. The government didn't issue a statement through a right-wing podcast stating that the network better toe the line or get it's affiliate license revoked.

You are right, this has happened before. This is far more like the purges of the red scare. People were just (perhaps naively) hoping society had progressed from where we were ~70 years ago.