I once saw a CEO who wrote his own Web Framework and forced the entire company to use it.
At the time, under the influence of React, the idea was to "build web application sorely based on Functional Programming". Since after years of trying no one could figure out what that meant, the company ditched the CEO and ended up wasting a couple years of work.
Step one was hire everyone the guy had worked with at his previous company. They were all winforms / excel / SQL / sharepoint / office developers from big finance and had no idea where to go really. None of them had even touched asp.net.
Cue "what's popular". Well that was Ruby on Rails back then on top of MySQL and Linux. 4 people with zero experience pulled this stack in and basically wrote winforms on top of it. Page hits were 5-8 seconds each. Infrastructure was owned by SSH worms and they hadn't even noticed.
I think I lasted two days there before I said "I'm done".