The problem with (1) is now you've completely stagnated the market, and if your competitors choose either of the other options you're left lagging behind and you lose sales.
The problem with (2) is now customers of older phones will be upset that they didn't get the full upgrade for reasons they don't understand. The iPhone 4S and Siri or the iPhone X and Animoji show the reaction you should expect.
The problem with (3) is now you have planned obsolescence and old phones just become throw-away leading to an ecological disaster.
None of these are good options.