This is a unit-shifter attitude. And I'm not trying to be rude, you need sales. But if you ignore long-term quality for short-term sizzle, you lose, at least if you're producing something like Debian.
If you don't understand why something like this is important to get right, I'd suggest maybe finding out why other people do actually care about things like this.
Or maybe reflect on why Microsoft spends so much money and energy on backwards compatibility.
Microsoft spends so much money and energy on backwards compatibility because it's good for developers; it lets them focus on solving problems, not tracking the frameworks they need to solve problems.
The Microsoft approach would be to support `which` forever. It's not a big enough quirk to justify removing it, and it's essential for some people's development process.
If you don't understand why something like this is important to get right, I'd suggest maybe finding out why other people do actually care about things like this.
Or maybe reflect on why Microsoft spends so much money and energy on backwards compatibility.