All the other transitions could be handled by virtualization and emulation, and the software and the corresponding data files could be copied between file systems and drives, so if you have built a workflow around a legacy app, you could still access it on new hardware.
But iOS being such a locked down and closed platform means there is currently no way to preserve legacy apps or the data stored within installations. This is why dropping 32bit legacy app support is such a big deal.
Seeing that Apple is the most valuable company in the world and they have a long history of abandoning legacy software (Apple //e, 68K, PPC, and soon 32 bit x86) and moving customers with them, that statement doesn't jibe with the reality on the ground.
What are the chances that people won't upgrade their iOS devices because they want to run an abandoned 32 bit app?