I also have noticed this in SF. It becomes most frustrating when I want to travel to a location using routes I am unfamiliar with or don't ride often. This means I can't off the top of my head guess when the next bus would be coming before choosing that bus route. In that case I usually pick a live route app like Transporter to see how long of a wait till that bus comes. Unfortunately, that time spent in another application can prove costly if you are in a hurry.