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It is "Trends" that users and manufacturers see, when they are planning for the future.
You don't make many plans for a falling product market.
What you plan for is how to get out of it.
The Cycle of development plans for Dslr's was probably pencilled in for the next ten years. The relative success of the mirrorless has almost certainly cut those, to cover only those products that were already in and advanced stage of development, or those that could be adjusted to a much shorter time scale, and at the same time still be profitable in the much shortened production life, and for which a ready market and profitable sales could still be forecast.
Electric cars are not yet a viable mass market product, but Honda has already made a production plan, that entails the closing of conventional car factories.
They have done it at "this time" partly because Brexit has forced a slightly premature decision on to them. But it is mainly a decision based on pollution legislation and the inevitable trend for clean energy. And also with their own upcoming zero duty trade agreement with the EU in mind.