Why should one waste years studying instruments, if one can do music just fine with chord track and virtual drummers and such. After all, music is for fun. If you get fun out of loops and phrases, why not?
I bet most Cubase users are not pros, but people who do music for hobby, for fun. Which doesn't mean they don't take it seriously. They just don't make big buck out of it.
Actually, btw, those who use Cubase to make money should never complain about prices - even one session should cover your Cubase license. If it doesn't, that is not really pro. Pro means profession, profit. For pros Cubase is dirt cheap. But for hobbyists it is quite expensive. Those who complain about price are not pros, even one microphone costs more than Cubase license, and what can you do with one mic anyway... I dare saying that Cubase is hobby software, which is being used by pros too, at their own risk.
For hobby fun, Cubase is very capable and quite stable, and I like the direction it is going in, chord track and virtual musicians and so on. Using Cubase makes you feel you have a good machine in your hands, makes you feel like a real pro :)