On the contrary, large systems have to restrict what their build system does because otherwise the complexity becomes unmanageable. I used to work on a large codebase (~500 committers, ~10MLOC) that had made the decision to use Gradle because they thought they needed it, but then had to add increasingly strict linters/code review/etc. to the gradle build definitions to keep the build maintainable. In the end they had a build that was de facto just as restricted as something like Maven, and the Turing completeness of Gradle did nothing but complicate the build and slow it down.

And sure, maybe having a restricted build definition (whether by using a restricted tool or by doing code review etc.) moves the complexity somewhere else, like into the actual code implementation. But it's easier to manage there. The build system is the wrong place for business logic, because it's not somewhere most programmers ever think to look for it.