It was very reasonable to imagine that if the API ever stopped being free, that the logical next step would be "paid access" rather than "no access". And that if Twitter was going away, we'd have some warning in advance (as we do now - building a business that relies on Twitter is a much dumber move today than it would have been a year ago, obviously).

I think the businesses expecting Twitter to remain relatively stable for the next several years were the reasonable ones here, yes.