[Serious] Why are older maps rarely reused now?

So, this is something i have difficulty understanding. There's a community of people screaming about map design. In my opinion BF6 maps are mostly fine / good enough compared to 2042 but they still do not evoke the same feeling like beloved maps of older titles in the franchise. I mostly play rush/breakthrough so take my opinion for what it is.

Now, why are these older maps not being recycled? The reworked operation firestorm exists, sure, but i don't think it benefited from the rework. I'm completely understanding that you most likely cannot just simply copy-paste map files from one engine to another but you'd think your life as a map creator/designer team would be way easier if you can create a map based on an existing, working well, layout.

Maybe some of you have some insight into why this could be the case.

I don't want to just dunk on DICE a la "are you guys stupid?" because surely that's not the case. Even from a economic standpoint: wouldn't you be able to create maps quicker this way, therefor paying less hours in wages? Couldn't you prey on nostalgia with a "back to karkand, again", "best of BF4", etc. map pack for, say, 20 bucks?

I know we got the map editor for portal. And that's great and surely the community will create some awesome things... but you know, having offical older maps or mappacks would be nice too if we already lost dedicated self-hosted servers.