Hah. Distort reality? Sorry if that doesn't meet your expectations. I'm just speaking from personal experience. I've had 8 hour brew days using my mash tun / turkey fryer combo. That means setting up, gathering materials, cooling, pitching, oxygenation, washing, drying and storing. These things add up, especially if you are doing a recipe with an extended mash, longer boil, etc.
That's fine, that you're speaking from personal experience. But I think that I'd quit brewing if I had 8 hour brew days!
Depending on if I'm fly sparging or batch sparging, my brewdays vary from 4-4.5 hours total, including clean up.
Remember that we're talking about the system and comparing them. Sure, if I was poorly organized I could take longer. But I'd take longer than most at BIAB also. A well designed three vessel system compared to a well designed BIAB system should be what we're talking about.
A mash takes just as long, so saying "an extended mash or boil" taking longer in a three vessel system just isn't accurate, as I'd assume that you would do the same mash or boil with the BIAB.
The differences between BIAB and "traditional" methods may involve sparging differently (or not at all) and the lautering method. That really should be the only differences. Mashing, recirculating (if done), boiling, etc should all be the same.