Yeah; you've gotta pick your poison. Either you sometimes end up with multiple copies of numpy installed, or sometimes pip errors out and will randomly, at the worst possible time, refuse to install the dependencies of your project. Having experienced both problems a lot of times, I'll take the former answer every time thankyou. I never want surprise, blocking errors to appear out of nowhere. Especially when its always the new team members who run into them. Thats horrible DX.
Having multiple copies of numpy installed isn't an emergency. Tidy it up at your leisure. Its pretty rare that you end up with multiple copies of the same library installed in your dependency tree anyway.
As for debugging - well, debugging should still work fine so long as your debugging tools treat foo-1.x.x as if it were a completely distinct package from foo-2.x.x. Nodejs and rust both handle this by installing both versions in separate directories. The stack trace names the full file path, and the debugger uses that to find the relevant file. Simple pimple. It works like a charm.
> For web dev and something like requests, it's just not as big of a deal to have a bunch of versions installed.
I think you've got it backwards. Its much more of a big deal on the web because bundle size matters. You don't want to bundle multiple 150kb timezone databases in your website.
I've also worked on multiple web projects which ran into problems from multiple versions of React being installed. Its a common problem to run into, because a lot of naively written web components directly depend on react. Then when the major version of react changes, you can end up with a webpage trying to render a component tree, where some components are created using foreign versions of react. That causes utter chaos. Thankfully, react detects this automatically and it yells at you in the console when it happens.