I am not an expert at all, but I suspect something:
If the software allows a second license on another computer, this would offer an „easy“ reverse programming possibility to actually crack the licensing system of the programm. Then the market would very fast get flooded with cracked versions of the application, which means the end of revenue, the end of further developement etc. If my suspicion is true, it would explain why Steinberg quite successfully should go against this road. In the long run it might be to our own benefit, if the system stays that restrictive.
Having said that, this issue is the only reason, why I am sticking to my old software for notation as long as I can…