You're assuming that it's an efficient market. But irrational ideas can make a market inefficient. This presumably gets sorted out in the long run, but that takes time.

In software, one source of irrational ideas has been the management models that were developed for industrial and manufacturing organizations. Since building software is a design process, not a manufacturing one, these models don't apply. The industry is slowly figuring that out, but that has left plenty of room for an inefficient market in the meantime—middle managers being perceived as more valuable than programmers and all the rest.