your system stopped counting the months of my subscription at 48 months.
First, how about you let me speak to a human? Your programming is faulty, and only a human can address it.
I have been seeing the same "It's your 48 month anniversary..." message, several months in a row. The channel knows my commitment, as do the regulars in chat. So what matters most is fine, but this is still frustrating. I'd like to see an accurate, properly updating count, each month.
So how can you improve subscriptions? Fix the coding bugs. I saw another user, a streamer, complain about needing a calculator when they see a fan has been subscribing for over 80 months.
That means what you have is a hidden error, one that doesn't occur all the time. You could have hundreds or thousands of subscribers who have the same problem, who just gave up on trying to get through to anyone at your organization.
Another thing you can do with subscriptions is just charge one price for subscribing to Twitch channels, and let a computer share out the money to the channels we watch. Every time we add a subscription for $5, we get that much less out of all our subs, because we don't magically have more time.
40% of US household can't pay an unexpected $400 bill, out of savings, so most people simply don't have enough money to subscribe to every channel they want to watch.
And your cost is based on server access time, not by how many different channels we follow. So your cost doesn't scale up with number of subscriptions.