It also got nuked from orbit by European regulators. The ecosystem has a huge installed base but no future.

Isn't it only using standard ble hardware anyway? So what's the problem?

They are both using the same physical layer, but the ANT+ protocol scheme is more amenable to ultra-low-power implementations than BLE is. The European belief that my wheel rotation sensor needs privacy through encryption has effectively outlawed the low-power attributes of ANT+ for future hardware.

I think it’s more about the ANT+ sport heart monitors.