I think something that's being underestimated here is that often people greatly over-estimate their availability for this stuff. Even a 3-hour session, which is pretty short for sessions I've been part of, you really have to plan your whole day around, and they may simply have not realized the level of commitment that would require, or at least been prepared for it. I don't play right now, and haven't for a while, simply because I cant make that level of commitment, and it would be unfair to the rest of the table to have to deal with my unpredictable schedule.

i don't think players are conditioned to expect you to be their little court jesters performing for them on demand, and i think it's really weird to make the case that they do

your player probably just got into dnd through something like dimension 20, which has its sessions edited down into 1 hour slots, but relatively seamlessly so you can't tell if you're not looking for it

I thought you were going to take this in the direction of unrealistic expectations about how long a session takes. I've always been really amazed at podcaster DMs' ability to get so much done in a 1-2 hour segment. When I used to DM I felt like I got the same amount done in about twice the time.

I mean, thats honestly going to be a thing that happens whenever some people get into something new through a different medium, really. Warped expectations are a thing. We've been dealing with it for decades with people who come to D&D/TTRPGs from video games, and expect the in game NPCs to act like theyre from skyrim or something. It's honestly not that much different, only with a different set of preconceived notions.

That may be a reason for it. If so offer them the opportunity to just watch, to consume D&D as they do podcasts. They can leave whenever and it won't mess up the game, but it also may get them more interested and want to commit to actually playing.

There's only one pause button I know that works on GMs, "food's ready!"

That'll pause any game. Though it may pause it in 10 minutes, as sometimes you want to hit a stopping point.

I found Pathfinder society scenarios are a good Start. 2 or 3 encounters, most are done in 2 hours, easy to adapt. Way less pressure than a 20 level run.