I agree with Jev.

We are moving to a world where monthly payments on everything is the way of the future. Phone bills were the start. Remember when your phone bill came three-monthly?

I reckon we will see more and more of this monthly payment model across not just software, but a huge range of things we use. If most are like me, I work on a monthly household budget, and put aside money from my income above what my regular bills are as savings. These savings are what let me buy things like LR, Photoshop, new lenses etc. I believe the finance guru's have realised that is how most people budget, and they have also realised that some companies and products can be shifted from the savings component to a piece of the monthly expenses budget, rather than a bit of the savings every now and then. They know that once we incorporate an amount into our monthly expenses, it becomes a part of our regular lives, rather than a direct decision to spend from our savings.