True but they aren’t really fast food but more of a sit down place. However they can still provide fairly quick service.
I go to different breakfast places and at least one of them (Maria’s in Salem MA), even when they’re crowded they get an omelette or pancackes out to you in a few short minutes (at the counter, etc.)
Weekends can have long waits at some breakfast places. But these are more of the sit down places (such as IHOP) rather than fast food-order-at-the-counter-or-drive through.
Diners and some breakfast & lunch places can often offer breakfast “all day”. (And some stay open all night on weekends for those craving an omelette at 3 am) In some cases they’ll say “breakfast and lunch every day but Sunday where we do breakfast only”.