Is MUCH, MUCH larger than it might first appear. Don't mistaken the early adopters.... largely comprised of intensively managed type I diabetics as the full market. They represent only a fraction of the evolving market.
a) inpatient glucose monitoring of diabetics in ICUs, step down units, and on most medical floors will become standard of care (and DXCM is poised with Edwards on this front).
b) nearly all insulin-treated diabetics (type 1 AND type 2) will benefit greatly from CGM since nearly all of these patients manage their insulin dosing at home. CGM enables better choices by lay people in choosing their insulin doses, and will therefore become standard of care.
Technology will make it cheaper and easier, but that should not affect margins due to economy of scale in both manufacturing and insurance eligibility determination.