This is already the way it works for PBX's (Score 2, Interesting)

This is just an example of the way things work in IT. i.e. the vendor lock-in.

I've seen phone systems like this. You buy the hard ware and there are cards giving lines which have to be activated individually.

So there is custom firmware or an OS per line/port that needs to be paid for before use.

-Kastor