The Liberty XL2 looked promising as a 2 seat IFR trainer but it never really caught on. It was expensive and for a lot less you could buy an older 4 seat 172 or similar with all the glass and mod-cons.
It would appear that the same thing happened to the Robinson 22 in favour of the 44 with sales dropping off significantly.
I suspect you can blame LSA's for the demise. Gone are the days are someone wanting to spend a quarter of a million on s new 2 seat trainer. Piper tried a new 2 seater with the Piper Sport, Cirrus tried the same but neither took off which is all very interesting really.