I'm not sure there's anything to disagree about. I fit exactly into the group you describe: 2 weeks ago, I received a new 7+ after the yearlong warranty on my old 7+ expired; insurance covered that. However, since the acquisition of my new 7+ is within the 30-day window, insurance will, in fact, also cover the upgrade. It was made clear to me that if I had not been within that 30 day window, I was free to pay out of pocket for the upgrade, but insurance would not have covered it. In that case, I would have waited a year for the new 7+ to go out of warranty, and then the G4 upgrade would have been covered.
So I don't know what you mean when you say insurance "isn't involved." It's absolutely involved in how Dexcom gets paid for the new units, if at all.
For new, first-time customers, pump and CMGM makers might be more willing to "give" the system away, since that brings them new customers in a competitive market. My first Dexcom unit, the 7+ was paid for however (insurance). I would point out, though, that I still had to give the insurer a strong justification for switching from my Medtronic CMGM in order to get that to happen.
The bottom line is that Dexcom needs to find a way to be paid, by somebody, for as many of its devices as it can, while still expanding its market share in a competitive niche. For most current and potential patients, insurers hold the purse strings and their decisions will impact Dexcom's policies.