Single developer shouldn't be that big of a factor in slow development and complete media silence for six months to a year on end; any half-decent developer can churn out an update every week, whether it's a new feature or just a bugfix. That's how you keep people excited about your program, and how to prevent it from seeming stale and dead.

I don't use it; I just know that this is the reason many of my coworkers are moving away from it. I've heard concerns about it breaking on a future OS upgrade, or just failing to keep up with others in features.

If you're looking to lose any and all good will you've established, charging all previous customers $70 to get updates is a great way to do it. ST2 dev is dead, which is what matters to the people who already paid for the product.