One thing I’ve wondered about is, isn’t the cost of checking for the failure case in the good case all the time actually worse (even if only slightly) than the cost of not throwing, which is nothing?
There's indeed a predictably present cost for checking for failure all the time. Exceptions, depending on the implementation, often do come with runtime overhead too. If the determining factor is a slight performance gain of exceptions over ubiquitous checking, that would be an exceptional (ha) case. I daresay there are almost always other more salient factors, if harder to rearchitect around.
