This would be a welcomed feature. I carry a small pouch filled with SIM cards.
The idea behind the talks is a universal standard for embedded SIM cards (“e-SIM”) that are built into the phone and not user accessible. These subscriber identity modules would allow customers to sign up for service on any network they wanted, then allow them to switch at any time (obviously with some limitations placed by the carriers).
The one caveat is that most carriers suck at anything software. Case in point: Movistar in Colombia hasn’t implemented visual voicemail, eight years after iPhone’s debut.