You very may well be right, however, there are more 20.1's out there then you think. Most people don't part with them, and from my experience they seldom contribute to the forums. I don't know what the current 1.6 sells for but I suspect its in the high one thousand dollar range, a jump to 2500+ would price them out of there market- lets face it a lot of 1.6 buyers are making a stretch just to get into a nearly $2000 speaker and all the equipment required to make them sing.
You are also mistaken about a better crossover on the 20.1, they use the same horrible components they use through out the line. With the push pull driver it demands larger values(of caps/inductors) for the speaker to function, and one less inductor then the 3.6. That's the extent of being a "better crossover", I've looked into on more then once before. I am not saying the 20.1 doesn't have greater potential then the 3.6, however at this time(and in particular with my current room) its not worth the price of admission to me.
If they were to increase the 3.6 or the new version of it to $5700, they wouldn't sell. The speakers are poorly constructed and use cheap components and wouldn't sell nearly as well. Competetion is getting more fierce in the sanely priced marked, pricing yourself out of the market wouldn't work with out addressing these issues. In particular when your product looks and feels cheap compared to the competetion in its current price range.