yes. if you buy something then its forever. unless you have it reposessed. its like a TV, once you buy it, no need to give it back.
You may not understand how a lot of editing software works. Final Cut Pro, for example, leases you a yearly license. You don't own it. Same for a number of 3D animation packages I've worked with (3DS Max I think is one like this).
It's a way for them to get constant revenue streams from business/corporations by wildly inflating the costs. So instead of buying Vegas 7 and keeping it for 5 years for a 1-time payment, they force you to pay every year so you might as well upgrade to the newer and newer versions (hypothetically -- I don't know if Sony follows this plan).
It was a valid question in the software world.