The problem is a plugin is only worth what people will pay for it. If 95% of people only buy a plugin when it's on a flash sale, that's all the plugin is worth. Everything else is just smoke and mirrors of marketing.
All plugin subscriptions should be rent to own. That way if I take a gamble on a year I will at least have the option to have credit with the company to own something if there's a product I desire.
And as far as I can tell, month to month isn't even available yet.
They had rent to own. Not sure how often it was used, but You can’t do rent to own on a full subscription. Giving people full access to everything you make and then letting them cash out 100% sounds like a poor business model. They’d have to go back to previous model of pick 10 plugins to pay off, or they would need to say that a certain percentage of your subscription fee goes toward a buy out.