It's not because of pump issues but more glucagon stability and secondarily whether bihormonal is clinically advantageous.

Tandem is working on a dual chambered pump.

https://diatribe.org/jdrf-and-tandem-diabetes-care-announce-...

Yea, but "working on" is a bit different than "readily available and trusted to function well". Everything is harder with two delivery pumps.

The pump isn't the hard part.

Yes, but the "patch pumps" like the Omnipod are small enough you think patients might tolerate 2 of them? Maybe they've already asked, and people wouldn't tolerate it.

Possibly. But it's more than that. You have site issues, even with one pump, that you need to navigate. There are only so many viable places on a body to attach a cannula for good absorptoin and, while small, these things aren't _tiny_ (especially the Omnipods where the site holds the cannula, pump and reservoir).

It'll be a while before we see highly reliable and well-tested dual-reservoir systems is my bet.

The complexities of balancing insulin and glucagon in a two-pump system are also high. And the feedback loop from sensors that detect BGL aren't super fast. My kid's Dexcom works on a 5 minute sample loop now. So you can't make decisions fast and when you do, you can't course correct a bad decision quickly.

I love that people are working on this stuff. The folks at https://wearenotwaiting.net/ are amazing and we even use NightScout here, but the fragility of the systems are stark and it'll be a ways to go before it's not just the brave pioneers pushing these frontiers for T1Ds.