Subscriptions are a good business model for something that people either
need or
can't get anywhere else. You pay rent because you need a house to live in. You lease a car because you need to get around. You want the local news so you purchase a newspaper subscription. However, once the internet came along and the news was 'free' the newspapers started to see subscriptions drop. I have a XM radio subscription because that is the only place I can listen to bluegrass radio.
Subscriptions can also take a quick death when financial times get hard. We pointed out the drop off in newspaper subscriptions. If I take a hit financially, the XM radio is gone. Bluegrass is nice, but it is not a need.
Microsoft is testing the waters with the Office on the cloud. Lots of reasons I don't like that. But last I heard, it wasn't doing well. People still wanted to 'own' (license to be technically correct) their own version of Office.
Software can be very similar. I may like using Cakewalk's Sonar, but I don't need to use it. I record as a hobby, not as my business. There are times when I may go for months without recording (like now when I am in school). Do you think I'll pay a monthly subscription for something I don't use? Nope. Can I find other alternatives to Sonar? Yep.
I sincerely hope that Sonar doesn't go down the road of subscription only. I believe it would be a bad business decision. I know for me Sonar X3 would then be the last version I would have.