You know the current procotol that setu app uses is way more battery consuming than apple-google's bluetooth only approach.
I wonder how those poor old phones will survive with it.
(I don't wish to engage more because I don't think you are looking for a good faith argument here because android app released by the government won't work on those Nokias and I don't see why you can't have two different appS with different level of efficiency because you will need two different apps regardless?)
Yes, those protocols would be available to any cell phone in the world and old devices to the same extent as any other legally-mandated protocol would be.
For example, if government can order than Nokia release a privacy-harming contract-tracing feature, then the government can instead order that Nokia release a privacy-enhanced version based on the Google-Apple protocols instead (or any other better protocols people have developed).
It would be more effective for the pandemic too, because you want maximum interoperability.
And it would be more effective for the pandemic because you will get better compliance too. If people know they are 100% tracked with full transparency they are more motivated to find ways to cheat, especially when doing something "disapproved" (like seeing your secret lover), which is not good for countering the pandemic. People will definitely find ways to cheat the tracing if they are motivated.
The exact reason why there are lockdowns the world over instead of everyone doing nothing while waiting for a vaccine. Or why the human history is filled with flawed and working solutions for everything instead of perfect and imaginary solutions.
There might be better protocols or specs available. But no one other that a doomsday cultist can afford the bodies to start piling up while doing nothing instead of doing something.
For examples has Nokia releases a protocol?