I think that Shimano is busy getting the 10spd and Mi2 out than a internal crankset, IMO
HS has amazing shifting action and great ground clearance, but it only work with frame that has ISCG tab. ISCG adapter would not work (well a few guys on MTBR has done the conversion on the Nomad and it's working great for them.) because the overdrive mode HS put a lot of torque on the tab I guess. It's more popular among FR/DH bike. Lyskey put it on the hardtail, I put it on my XC bike.
In additions, most current frames are design around the middle ring pedaling with compromise on the big and small ring. Some designs are not affected by the ring size like Maverick Monolink design. HS is not that heavy only add 2 lbs which is not bad for what it has to offer. My seven was 26 and change now it's 28.5lbs. If compatibility issue is not the factor, I wouldn't mind putting HS on more of my bikes.