"[M]any insurers have begun moving toward a 'supermarket' of various offerings, most likely amassing many segment-centric assets.... [Tailoring] health plan offerings reactively to consumer demand ... is achieved by adding hybrid products that address specific customer needs or by stitching together a marketplace of add-on point solutions.... [S]ome insurers are using the startup approach to design new care models and coverage plans. The risk is that it requires scale to succeed."