From: Lorenzo Colitti Sent: Wednesday, June 10, 2015 5:07 AM
getting rid of NAT. Today in IPv4, tethering just works, period. [...] IPv4-only apps always work.
Wow. If your phone just "always works", you certainly lead a charmed life.
A model where the device has to request resources from the network before enabling tethering, or before supporting IPv4-only apps, provides a much worse user experience. The user might have to wait a long time, or the operation might even fail.
Far better that the user stare at the useless android brick in their hand that is incapable of connecting to the network at all. Maybe you should try taking a poll of actual users? Dear user, would you rather: A) have a phone that connects to the network and the most part works barring some side cases B) have a phone that is incapable of connecting, but saves you from being unable to use certain functionality that otherwise would have been unavailable. By preventing you from using any functionality at all.