Because in reality, with large teams, communication is expensive.
Containerisation allows reproducibility, in a self-documenting manner. Delivery can be automated, depended upon to run, in a totally system configuration agnostic manner. It allows projects to deliver their software in a way that it can be ran, instantly, with a single command (image download not withstanding).
I've worked heavily in service software engineering for over a decade now, and with docker since 2013, and it has changed everything. There will be some people who don't fully understand it, but perhaps they don't have the problems that it solves and thus don't need it.
Alternatively, they /could/ just be suffering without realising there is a solution.