It depends on `image` which in turn depends on a number of crates to handle different file types. If you disable all `image` features, it only has like 5 dependencies left.
It is also important to note that this is not specific to Zed. As someone else have mentioned, it is a cultural problem. I picked Zed as an example because that is what I compiled the last time, but it is definitely not limited to Zed. There are many Rust projects that pull in over 1000 dependencies and they do much less than Zed.
I just went to crates.io and picked a random newly updated crate, which happened to be pixelfix, which fixes transparent pixels in pngs.
It has six dependencies and hundreds of transient dependencies, may of which appear to be small and highly specific a la left-pad.
https://crates.io/crates/pixelfix/0.1.1/dependencies
Maybe this package isn't representative, but it feels pretty identical to the JS ecosystem.