Depends on what you mean by "figured out". Yum was capable of dependency resolution 15 years ago, maybe more, but was unbearably slow compared to apt-get. Maybe dnf solved that, maybe yum is faster now, I don't know, I switched to Debian more than a decade ago and didn't have a reason to retest RH since.

Even on the slowest systems I still have access to (64MB VPS, RasPi 1), apt-get is reasonably quick and responsive.

It's been a while since I've used it but yum used to tie up my machine pretty badly on significant upgrades. After reboot it could take hours to finish applying the upgrade, during which time the machine was usable. Apt has never given me that sort of trouble.

>It's been a while, but my understanding is redhat figured out dependency resolution too, though.

About 20 years ago, give or take.

Maybe 15, but I do recall using redhat in 1998 and getting things like you can't install foobar.rpm because it needs /usr/lib/libsomethingcool.so.4 and then plugging in that file name to rpmfind.net to figure out what package I needed (maybe it didn't need to be that hard, but it wasn't obvious that it could be easier)