Thanks for all your comments ...

Definitely agree that it was cutting it short ... well under the guideline of 90min .
However as a frequent traveller this was an educated risk : early AM, weekday, Dallas, United terminal -> no security line (and actually there was none) , no long walk in the terminal , many Easychicken machines with no lines whatsoever ....

I would note that the 90min with bags to check-in standard recommendation was not even the problem here because the bag got in ....

What I find puzzling is that they would accept a bag without checking you in ... and that they could not print the BP in coach if they weren't allowed to pull the upgrades ... or at the very least give you a DM card to go through security and sort it out at the gate .... When the curb side folks said they could not do it I did not push it further as I expected that the Easycheckin machine would be able to sort it out (with the built in phone help if needed) it's really only when that failed and that I had to deal with the huge (absolutely unusual) line that looked pretty much unmanaged (first/ elite mixed in with economy .... ) that the real problem started ...

I agree that I should have done OLCI ...

Regarding the 100$ fee I intend to discuss this with customer relation ...
(choose not to argue the point when I finally reached the counter)