> It's a lot of extra time and QA for each variant of a release.

In Vivado, it's the same release for the free and expensive builds on both Linux and Windows. It's just a question of the installed license file/license limits.

> such as the Linux builds require proprietary 3rd party code with royalties, and they chose not to eat that cost.

This seems unlikely for a multitude of reasons.

This ignores that their revenue comes from selling chips. The software enables that. No software, no chip sales. This can only have a negative impact on their sales.