well... that's a tough one.
I DO think the 2050's have a different sound signature to the six nine one that I do enjoy/prefer over the entire 'range'... but it's not a GIGANTIC performance difference that one can take advantage of in a home setting. It is a change that is slightly > more than just 'Subtle'.
In terms of the economics, I am okay in spending the money for the difference... I really don't measure things in a cost versus reward manner because there will always be a uncontrollable 'barrier to entry' price associated with equipment change, but I would NOT have done the swap had the Heritage model not had the same driver. Keeping the driver swap in the 'Klipsch' approved setup made it okay for me on a personal level.
However, I am very curious in trying a Beryllium Diaphragm Driver... I just like/prefer the sound of beryllium and I think the 2050 gets me partially of the way there over a stock six nine one.
To your original point... I do think that most would be MORE THAN happy with a 402/691 and AMT set up. I am trying for a bit more.