Sometimes is the organization itself to be badly shaped, maybe with separated budget between development and production, so managers aren't enforced to save somebody's else's budget. Sometimes the cost of ownership is perceived as a "normal mess" and becomes alarming only when it's totally out of control, which can be ten times bigger than acceptable, or more, due to the "buffer effect" of the dedicated people.
Sometimes is the overall project planning that plants the seeds, for the "touch and go" architect. Time is allocated mainly before the whole development starts, so the architect can't see the developers in action. I mean, architecture is challenged by development, and by time too: developers could not behave as predicted and find different ways to solve coding problems, and evolving tools and framework could make the balance of forces that drove some design choices not any more valid (that's a good reason for architect to document the reasons of their choices). It's often not a matter of being right or wrong, but instead a matter of seeing the whole picture , which is - obviously - much easier at the end. Following a project till the late stages clearly makes a better architect, but seeing everything possible from the early stages is what software architects are paid for.
There's some sort of analogy with the traditional drawbacks of the waterfall approach with the analyst role. Agile processes have put of a lot of efforts in introducing iterative release cycles, which are just a way to anticipate real feedback as much as possible. Iterating architecture, for some reasons, seems to have a longer path, but I'd say it's probably the same problem, only with different category of users.