At my previous company there was an in-house training, where the first three months were dedicated to the training of a new employee. The training consisted of both the tech stack and the development and business processes used by the company.
As a result everyone knew how things worked and everyone by far exceeded the minimum level of knowledge needed to meaningfully contribute. It was a great department to work in and I miss it still.
Sadly, the company had that insane policy of only 3-4% annual raise irregardless of performance, so most people, including me, would leave after a few years.
