It's very rare for a rewrite to make sense unless the underlying stuff has so fundamentally changed you don't really have a choice. (For example, DOS to Windows. You have to scrap your UI completely.)
For some tech choices there was just one clear path from where we are to where we need to go. But for others, the overriding decision was more often than not that some team member had familiarity with the technology. Certainly not the only criteria but enough to tip the scales if it came to that.