- Get the user hooked into their ecosystem
- Slowly make the service worse / more expensive / different over time
- The user is paying for a subscription which feels like an investment, so they put up with more crap than they would otherwise.
Trust me. If you have a subscription for something, and you like it, it will change under your feet. It will get worse, and in effect, it will be taken from you.
I'm not paying for the subscriptions. If everyone moves towards subscriptions, I'll move into a shack in the woods. I don't care. I don't want your subscriptions. If you think subscriptions are a good idea I don't want to hear from you, and I wish you had no say in how anything was built.
[edit]
If the counter-point is that mobile apps will suffer, then good. I don't like or any want any mobile apps whatsoever.