Our move to subscription is not a "money grabbing" move, but a move to provide a reliable service to our users for the long term.
Maintaining a server to provide this service is a recurring cost and it isn't free for us. We rather charge a subscription now than having to pull the app from the App Store later when the new sales don't cover the server costs. (for example, what happened to MobileChat?)
$1.99 for a whole year of reliable push email is excellent value (and it says clearly in the App description - we aren't trying to deceive anyone). People spend more money than that on a cup of coffee a day.
Also, we are giving our existing users and apps a lot of attention. To say we are letting them "rot" is absolutely untrue. Mail Notifier 2.0 was released recently with a ton of new features our users suggested and more are coming later. If you seen the latest screenshots of TextNow in our blog, you definitely would not think we are letting our existing users and apps "rot".