When a software provider I use starts ripping out features I relied upon, I start looking for an alternate provider, one that isn't so eager to kill features. And in particular, I try not to learn or rely on any new features, if there is past behaviour of feature removal by the provider.
It's better to be careful - very careful - about what you add, and to have a story for migration, than to remove features.
This depends on industry, of course - in consumer web it's much better to risk pissing off a few customers but make the majority of them happy than to keep all your existing customers but risk losing out on a new innovation that gives a competitor a toe-hold. Enterprise SaaS probably has different trade-offs, and software infrastructure probably different still.
This paradox, BTW, could be thought of as the full-employment theorem for entrepreneurs. As long as it is rational for a business to avoid change for fear of having to remove or support it later, then there will exist changes that a company with no customers and no codebase could implement that no incumbent would dare. Some of these are bound to be useful to some segment of the market, and that's why you get continued disruption in technology markets.
It's better to be careful - very careful - about what you add, and to have a story for migration, than to remove features.