The longer you use WordPress premium themes and plugins, the more discerning you become as a customer. Customers only have a limited budget, so they are forced to thoroughly evaluate purchasing any theme or plugin ESPECIALLY on a recurring basis. If that plugin doesn't offer REAL value and quality; it's not going to populate too many arsenals.

We tend to purchase lifetime licenses once we know for sure the plugin meets these criteria, and we are confident in the developer and how they conduct business. I believe the developer should focus intently on the plugin, support and updates and not sweat the pricing.

I have noticed also that the more successful a plugin shop becomes, generally their pricing go up. Sometimes way up forcing existing customers to look at alternatives. Also, these bigger plugin developers tend to get sloppy and start ignoring their existing customers; ie. not announcing price hikes; announcing price hikes almost on a yearly basis; not fessing up to breaking a plugin; loosing all of their customers' accounts; making unauthorized changes to the customer's data, etc.