First of all, I agree that cargo blows the C/C++ tools out of the water in terms of ease of use. But I think it's even easier than newer stuff too. It's by far the best dependency manager I've used.

I haven't used pip-tools, but I have used pip, npm, bower, and other more modern dependency mangers that work for non-systems programming languages. Cargo has never given me any trouble. Pip has occasionally given me weird issues about things not being installed in the right places or on my path. NPM regularly required `rm -r node_modules` and starting from scratch. Bower has had the same trouble as npm. It's not that these tools don't work for me, I've always been able to google the error message and find someone with the same problem. It's that Cargo has never given me an error message that wasn't my fault like "This package doesn't exist" when it's a typo. It just works.