Nobody is claiming this is a trivial problem to solve but its also not an impossible problem. Other languages have managed to figure out how to achieve this and still maintain backwards compatibility.
Note that you will be expected to have familiarized yourself generally with previous failed proposals of this sort, and proactively considered all the reasonably obvious corner cases.
If you want examples then just look at one of the other languages that have implemented compiler / runtime dependency version checks.
Even Go has better dependency resolution than Python, and Go is often the HN poster child for how not to do things.
The crux of the matter is this is a solvable problem. The real issue isn’t that it’s technically impossible, is that it’s not annoying enough of a day to day problem for people who are in a position to influence this change. I’m not that person and don’t aspire to be that person (I have plenty of other projects on my plate as it is)
There are many people here who think enabling lazy imports is as simple as flipping a light switch. They have no idea what they're talking about.
This thread was a tangent from lazy imports.
And actually people do appreciate the complexities of changes like this. We were responding to a specific comment that that said “it’s impossible”. Saying something is “possible” isn’t the same as saying “it’s easy”.
Saying something is possible isn’t the same as saying something is easy.
If you were to have said “it’s a different problem to solve because of…” then you wouldn’t have had any pushback. But you didn’t. You said it “this is not possible”. And that’s the part that people were disputing.