Highly optimized and well defined solutions are by definition inflexible. Because they are the result of removing everthing which is not relevant for the task.

Highly optimized and well defined solutions are by definition inflexible. Because they are the result of removing everthing which is not relevant for the task. If you are a company handling thousand of letters per minute, then you don't have any reason to be flexible, because the task does not change between the iterations. I mean we are talking here about industrial level of optimization, not some dude in his small office stamping his three letters a day. Companies on such level optimize everything from highest to lowest levels, because any optimization can make a difference of millions of whatever currency they use. In that scale, nothing is simple, because everything can become expensive on the high run.