Maybe I’m just young, but I hate chalkboards. In college they were always way less legible than a whiteboard with a fresh marker—too little contrast.
If you see a marker... 50% chance it's dead, 25% chance it's barely alive, 15% chance it's legible from the back row, 10% chance it's fresh and usable the way you describe it. It's impossible to tell before you try.
After you're done with it, you need to remember to close the cap, or find a trash can to chuck it into (and make a call if the marker kind-of-still-works-but-not-really). Seems like a small thing, but adds mental overhead. And it's a big enough overhead that a lot of people don't do it. Otherwise, how would we end up with the distribution above in the first place?
Now teaching/explaining is a performance art. Doing the "wait, let me try another marker, is it better now?" dance ruins the show.
That's why mathematicians prefer chalk. The subject matter is already difficult enough, there's not enough bandwidth for all of that nonsense. Have chalk, will write. End of story.
My biggest annoyance with dry erase is when people leave markings on for a really long time and board gets stained.
The feel of writing with dense chalk is much nicer than markers, in my opinion; obviously in others as well. Some of it is just tradition too.
(as a bonus, nobody I know has screamed and covered their ears due to inadvertent scratch of whiteboard :P )
I'm also young, but I hate whiteboards. Much lower contrast than blackboards. Pens can't go over pens for emphasis or in a second colour. Pens basically can't be seen from the back.
My alma mater swapped blackboards for white while I was there, and I found the brand new whiteboards and pens far worse than the who-knows-how-old blackboards.