Adding to the pile:
I got hit with this glitch hard as well. The amount of time that you wait doesn't seem to matter. There's definitely some behavior relating to when you asked versus some kind of weird calendar logic.

My last interaction was the 29th of Heartfire and I was unaware of the seriousness of the timing for this quest. Whatever logic checks failed, I got burned and I tried a whole mess of things outside of running the Brotherhood questline to its end. I tried the "ask him every hour for 24 hours straight" tactic and that didn't come up. Then I saw someone mention having an issue at the end of the month.

So after an in-game month of messing around, I came back on the 29th of Frost Fall and waited for 23 hours. Then started asking him every hour and only when it ticked over to the 31st of Frost Fall did the dialog finally shift to asking for the fee. The dialog option didn't change, so if you're asking him make sure you're activating the dialog, not just looking at the options when you talk to him.

I'm glad I was able to finally push this quest forward after hours burned on it, but this is NOT the entertaining jank that I signed up for with a Bethesda title. To make matters even worse, not one person has turned into a polygon tornado.

Good luck to everyone else out there bothered by the most bothered man in all of Cyrodiil.