Good points. I took over management of a software development group that had a four server commercial product that was dependent upon having developers knowledgeable in all of the following: Windows, Linux, MSSQL, PostgreSQL, MySQL, C++, C, Java, C#, PHP, Perl, Bash, and Javascript.

The development team was very siloed. Nobody could work on anyone else's code, not even a little bit.

When a new developer approached me with a module that he had written in Jython, I almost lost it.