Ah, yes. My favorite topic. 
There seems to be a lot of reluctance, even though the number of packages like this is small. 275 at the last count. See the conversation here Insights into how poetry.lock works cross platform - #24 by jvolkman
Poetry and PDM already seem to work this way. So does uv if I’m not mistaken.
I’m not sure where that really leaves us to be honest. If major tools are behaving as if the feature doesn’t exist, maybe it’s not a great feature to keep supporting?
I do think that it probably should be it’s own PEP? Or an edit to an existing PEP? Feels like major scope creep to throw it into this beast of a PEP for Brett. Although I’m no expert on what’s easier here.