That said, Servo did seem to be one of the more lively places, so perhaps it will continue.
Rust seems to have a strong community of voluntary contributors, and could probably be run without company backing. Similar stories if you look at major FOSS projects such as KDE and Gnome - primarily dependent on a wide base of volunteers.
Then there are projects with a mix: plenty of volunteers, along with many commercial contributors - the commercial contributors tend to be more significant (certainly they add more code - but then they're the ones pushing new features for their customers) - but then there are enough volunteer contributions that the projects aren't dependent on the commercial entities. Linux Kernel, LibreOffice, Kubernetes, VSCode, come to mind. And with multiple commercial entities, it's not a tragedy if one drops out.
Then there are those projects with a single commercial backer, and fewer volunteers. Those are the ones that die off when the company drops out. The question is - is Servo in this category?
I am not too up to date on KDE, but Gnome is mainly pushed forward by Red Hat, and recently by Canonical. Unpaid volunteers certainly make a decent amount of contributions but the vast amount of progress comes from corporations, not volunteers.
Even the Linux kernel would never had taken off beyond an hobby project had not been for contributions from Oracle, Compaq, IBM, Intel engineers during the early days.
So yeah will Servo find such a benefactor, very difficult to say, but Samsung used to contribute, if I remember correctly.