Yes the XH59A had performance, but it also had many problems that technology back then could not overcome.
I’ve no doubt Sikorsky learnt a great deal from the XH59A, but I would suggest that without fly-by-wire control technology and material advancements allowing for a reduction in high vibrations for one, further investment at the time would have achieved little reward.
Igor Sikorsky did not invent the helicopter, but he was the first to build a safe and practical platform that could be put into production.
Clearly Sikorsky feels confident enough that the data gleaned from the X2 flight test program justifies a continuation of ABC funding to the next phase, this being the X-97 Raider.
As it’s UTC’s money (and not that of the US taxpayer) they are spending, clearly they feel they could be on to a winner.