When there are no more new buyers to sell devices, or new versions of existing software packages, the only way to keep the curve growing for shareholders and MBAs is to sell subscriptions.

It is also the only way to convince developers to pay for software.

Having a part hosted on some server is so much better than whatever anti-piracy schemes one can think of, and provides the continuous growth curve for printing money.

Thus subscriptions aren't going away in the modern software world.