Why would I pay $60 to use a calendar for a year? it makes absolutely no sense & it would mean my users getting used to it only to have to overhaul it and transfer all the data. No thanks, NOT worth it for any cost.
I also think you should know that your calendar actually does NOT have “the most features” nor it is the least expensive, believe me… I’ve been looking at allot of them, I wont identify them on here because that’s rude, but you’re welcome to email me and I’ll let you know.
In the end, its the subscription (& high cost of it) that I would need to actually make it work for my needs that is a deal breaker for me, you can add tons of “features” but if their not useful (in my case) they don’t count. So I’m not going to add a plugin that can’t be updated after a year, nor will I subject my users to instability of services because a plugin author decided 2 years down the road to increase the annual cost to a rate I’m not willing to pay.
You really need to consider that you’re asking people to stake the quality of their sites offerings on the fact that you’re not going to price gouge them once they have a heavy user base actively using the plugin.
It’s just not a good way to do business (for me) but it looks like it’s working out for you. If this ever changes are you begin charging flat rates, I’ll reconsider if I’m still in need but for now… That’s just how I see it.