At least two out of the three enterprise(ish) software companies I've worked at had their own in-house bug trackers, their own in-house build systems, and their

At least two out of the three enterprise(ish) software companies I've worked at had their own in-house bug trackers, their own in-house build systems, and their own in-house version control systems. (To be fair, the versioning systems were custom front-ends over Rational Clearcase at one and Perforce at the other, but still...) The third had it's own in-house monitoring and logging infrastructure. (One team maintained its own monitoring daemon entirely because they preferred to do that than learn how to use Nagios!) As you might guess, I was very frustrated by how much time I spent re-learning how to do the most trivial tasks when I switched jobs. So, yeah, NIH is a real thing.