I had a UA flight from IAD to EWR on June 26, it was delayed repeatedly until eventually being cancelled. I have a screenshot from United app showing it's been delayed 21.5 hours. I never got the email about the 30k and when I reached out to them on Twitter about it, they advised me to contact their regular Customer Care team.
The itinerary was the final leg of a longer itinerary and it's possible I hadn't checked in with UA because I saw it was constantly being delayed and proactively made alternative arrangements to just make the drive. That's the only reason I can think why they're not giving me the 30k compensation.