You are exactly right. Movie theater industry data from before the pandemic showed that upwards of 20% of a movie audience left the theater at least once in a full-length feature.
Re: Chicken and Biscuits--there seems to be a clear point an intermission could be put in--and might could help the show, actually. But apparently, the original plan of selling chicken and biscuits at this intermission was nixed by city officials, so they elected not to put in an intermission. Seriously, though, with the amount of coming and going in that theater, it is not really much of a disruption to nip out to the loo, as it were. Although, I very much agree that accurate running time--especially when the show starts at least 10 minutes after the appointed time--is a necessary change to the online materials. (I suspect without audience reaction, the show is 15 minutes shorter, but that is still longer than the stated time on official websites.)