Much of Mozilla's revenue comes from Google, of course. This couldn't be because Rust was, and is, outshining Google's GoLang? Surely not?

This article is so stupid. I've been following blog posts and such back then and even though nobody spelled it out, there was conflict between the Servo and Gecko camps at Mozilla. The C++ Gecko developers were afraid that they were about to be made obsolete by the Servo team. You can easily see this that this camp spread the idea that Servo was never ever meant to be a production engine, only a research playroom but OTOH a Firefox-branded VR browser fully based on Servo was slated to come out not too far after the layoffs happened (IIRC the roadmap stated a year later). The claim of Servo having been only for research and the roadmap of a production-quality Servo-only Firefox release are obviously at odds.

Here's the roadmap: https://github.com/servo/servo/wiki/Roadmap/c8c1a2fbee9fd3ea6e01943db96825516f8478e8 ("Our 2020 goals for Servo - especially the Mozilla staff - are aligned with the Mixed Reality efforts at Mozilla: Release a public Firefox Reality application to the Windows Store that is built on Servo and works with any Windows Mixed Reality headset, focused on delivering high quality immersive web experiences")