Originally Posted by BWinmill
The question you have to ask yourself is why? There are probably dozens of reasons why they are sticking to the older systems and a handful of reasons to modernize. It is a lot easier to build new infrastructure (e.g. in the 1950s when air transportation was expanding) than it is to replace operating infrastructure.
The same older systems that cause innumerable near misses each year? You'd figure the insurance adjustors would've forced it through by now.