RealFlight is actually somewhat unique in today pc market. They have done a number of things for their customers that are way out of the ordinary.

They had produced AddOns with earlier versions. With later versions they re-labeled that kind of package as Expansion packs. They had to move with the industry graphic hardware with new versions, and the industry doesn't do "backward compatibility". So their newer versions couldn't support the AddOn content. They listened to their older customers and took note of their discontent. Over time they rewrote the old AddOn content to work with the new versions. The AddOns are now free downloads that work with the newer RF versions. It cost RealFlight to do that and they made no profits out of the effort. They aren't your typical pc software company.

It's not surprising at all that they chose to market an $80 upgrade that benefits every customer back to RF3 (when the industry changed up the graphics). And that $80 is Tower's price, which will wind up actually costing me $65 to include the sucker in my next order.