As of just now, we've had 1323 contributors to the main repository, not counting Cargo, some crates, or the website, for example.
Mozilla is paying virtually all of the people who are working on it full-time, but there are a lot of people doing a lot of work in their spare time too.
> with the way things have been going the past few years
If you're referring to the projects which have been dropped over the past few years, I can see that. At the same time, Firefox is the core product, and Rust is already in Firefox, so dropping it doesn't seem likely. The amount will only be increasing.
Mozilla is paying virtually all of the people who are working on it full-time, but there are a lot of people doing a lot of work in their spare time too.
If you're referring to the projects which have been dropped over the past few years, I can see that. At the same time, Firefox is the core product, and Rust is already in Firefox, so dropping it doesn't seem likely. The amount will only be increasing.