At this point what stopping those people from going the full DIY path and building their own insulin pump ? In those days of 3D printers and cheap electronics t

At this point what stopping those people from going the full DIY path and building their own insulin pump ? In those days of 3D printers and cheap electronics this seems like it should be achievable (I'm probably in full Dunning-Kruger mode here please forgive me). Or even gut one modern commercial unit to get the fluid part but replace the electronics with something more automation-friendly.