Funny, to me the KEEPING the licensed themes is the best way to get more mechs. Here is why. We have been told many times the cost of a license (aside from the Beatles) is about $50 a game. For that price you get a lot of ready made music, sound bytes, artwork and even video. The savings in development cost alone will pay for the license. The other key reason is that licensed themes sell more. More machines equal more profit margin to increase the BOM or at least not cut it further.
In this day of stereo sound and high resolution displays, creating new characters and content is infinitely beyond the days of Gorgar and Atlantis.