I totally agree with you on the basics. Compare though with high level languages and frameworks. Every programmer knows that you refer to the API to get the most knowledge about modern programming - to use the language or framework that they’re using. Projects are defined all the time to include such tools. Engineers are interviewed to determine whether they can use them, or learn them. When a system comes along like HLL, that is designed to support sharing and reuse, then a similar situation exists for specialized application components.
In the circles I travel in APIs are almost treated like languages, people know C, and C++, and WinAPI, and .Net. So if you can teach your developers to think of the in house stuff as an API then it could work, of course then you have to really package it that way. At my first company, where we did the hardcore code reviews, we did that, we approached these common tools as our own version of the standard libraries that came with VC (that’s how long ago this was). We still ran into problem of people not knowing all the stuff that was there, but it did help. Since then nobody I’ve been with has been that ambitious.