Servo had two major roles within Mozilla - as an incubator for novel browser technology we wanted to ship in Firefox, and more recently, as a lighter-weight vehicle for Mixed Reality products. The latter has been the focus for the last three years, and those products now appear to be winding down. But the former was a huge success - both Servo's parallel CSS engine and its GPU-based graphics layer are now shipping in Firefox.
While it seems unlikely that Mozilla will continue to prototype things in Servo, we're still building lots of innovative technology (and writing lots of Rust code) directly in Firefox. A few of the teams have blogged recently about the work they're doing [2] [3], and I'd encourage anyone interested to check it out.
The Servo team accomplished a ton and left its ongoing mark on the Web. These changes are tough for everyone within Mozilla, but are not indicative of any change in strategy for Firefox. Gecko is alive and well, and there are no plans to switch to Blink.
[1] https://bholley.net/blog/2017/stylo.html [2] https://mozilla-spidermonkey.github.io/blog/ [3] https://mozillagfx.wordpress.com/