The main difference in a subscription scheme is that if you let your subscription lapse, the software ceases to run at all! In SketchUp's permanent license scheme you just lose support and upgrade to the next version. The software continues to run as is. As a result, there are a lot of people out there still using (for example) SketchUp v8 because it was the last version without the no-commercial-use restriction in the license for free/Make.
I also despise subscription licensed software. From what I can see it is nothing more than a mechanism to keep sucking money out of your wallet even if they have added/fixed nothing that affects you. The big guys went to this when it became apparent that people were no longer slavishly updating to every new release - because the vendors ran out of new things to add that were valuable to more than a specialized subgroup of users, or started making changes that were just "tomayto" vs "tomahto".
Frankly, there are enough long-outstanding bugs in SketchUp that the team could work on them to make a new release without adding any more features at all!



