A company can drop support of a legacy product anytime that they want to, once all warranty periods are over. There's no case of a class-action suit.
As for "If DJI drops support for the P3S, what are we to do with our birds?" Answer, fly and enjoy, why would you need their support once the warranty is done with.
Thank you for stating the obvious . I fully 'understand' that once the warranty is over, one should not expect 'support'. I was thinking more in line of ... if such support is terminated sooner than later. While I appreciate (for $$$ reasons) that a company cannot support a product forever, many companies out there keep on rolling out new hardware versions at often ridiculous paces ... just to push the urge to 'upgrade'. It used to be that all you had to do was upgrade software for bug fixes and enhancements. Nowadays, companies expect you to upgrade hardware as wll, and often the features in between are 'not' dramatic improvement. Example: Nikon and their DSLRs, e.g. D5100/5200/5300/... every year, ... come on, really?