I'm not sure I follow these concerns about "working in the future" - as long as you specify versions that work for you in your Cargo.toml file, that should work at any point in the future given that you use Rust 1.x.
If you'll want to update to always be on the latest version of each crate, well that discomfort about them potentially not working is part of the price.
If I come back to something, it’s because I want to resume active development. Keeping a dependency pinned at an old version makes that more difficult in various ways, so I personally value forward compatibility.
Not everyone does, and that’s fine. I just want to know what a library developer’s stance on it is before I try to use their library.
If you'll want to update to always be on the latest version of each crate, well that discomfort about them potentially not working is part of the price.