Please let's be realistic, they are doing the same thing like smartphones and they even want to evolve their hardware wallet into phone 
It's obvious that, like any commercial company, all they care about is to earn money. And forcing their user off an older product in order to make them buy again is... unfortunately too common and Ledger is clearly doing the same.
I am just saying that it's going to take time. The production of the old Nano S could stop in a month, but you are still going to be able to use your device and they will surely keep making software upgrades for it as well for some time until their clients either purchase a newer Ledger brand or switch to a different company all together.
They can easily halt the software upgrades whenever they want. Their production for Nano S may be already stopped or may be at the end of this year.
Still, I agree that it should take time. Of course, it depends on how hungry/evil they are. Normally it should take at least one more year from now until the updates will end, but who knows?
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Also, something you both didn't say (or I've missed) : it also depends on how other software will behave. I mean that unless something fundamental changes or some big flaw is found, I don't see why Electrum wouldn't support the Nano S for many more years after Ledger stops updating it.