I've always hated SaS models. All it does is give vendors a free pass to quit innovating. With normal buy to own version releases, they have to actually improve the product with new features to entice people to upgrade. With subscriptions, they can just sit on their asses and watch the money roll in because people don't have a choice. You can't just 'keep using the old version' if you're dissatisfied.
Yes i'm aware that buying adobe products outright is still an option. However that option is priced so high that very few people can justify the cost and be willing to pay it.