It's not so easy for small companies to change direction when they've established their business in a certain way in which they were able to develop for multiple platforms. Suddenly, the rules change, and because the Apple app store represents 80% of their revenue, all they can do is abandon development for other platforms and stick to Apple. They don't really have a choice...
i agree with your description of the situation, but what is your point? isn't this simply the nature of the game? i presume most of these companies exist in market economies, and that is how things are. there are no guarantees that investment will be returned or be profitable, there is always risk. conditions change.
surely you agree that it is a company's and developer's responsibility to devise strategies so that when change comes they can adapt and flourish, it is not up to apple to promise that conditions will never change