Bob the builder can we fix it? Bob the builder yes we can!
-- Bob the builder
Engineers, like Bob the builder, like to build things. it's in their DNA. It's what attracteed them to Engineering in the first place.
Since we're biased towards building things, we often don't use existing tools that'll solve the same problems. I once heard someone say that ABC stands for "Adapt, Buy, Create", meaning first try adapting your code, then buy a new tool, then create a new tool. However, Engineers tend to always be CAB, a.k.a. Biased towards building new tools.
Here's something that seems to happen all the time in the Enterprise (as a result of the biased nature of engineers):
Essentially, it's simply more fun to build things then to wait for the team that owns the process to get their act together. Additionally, the business priorities might not be aligned with the realities that a team is facing. This leads to lots of orphaned and duplicated tools.