Tools might be fine as GPL, but companies don't want to touch strong copyleft with libraries and subcomponents for fear of needing to disclose the proprietary a

Tools might be fine as GPL, but companies don't want to touch strong copyleft with libraries and subcomponents for fear of needing to disclose the proprietary additions. And one of the larger reasons to open source something is to get external involvement and funding in the project. So you don't want to license it in a way that will disincentivize contributions. Copyleft protects you from proprietary forks, but if your building common infrastructure with peer companies across different industries this isn't a concern, instead maximizing involvement is the objective.