First of all, my sincere and heartfelt thanks for using “unfinished tasks” instead of that horrid neologism “technical debt.”
I forget if I said it before but breaking large projects into pieces is not new with these silly methodologies, we were doing that thirty years ago and I did it myself in projects I did solo (which I have done pretty much always for over thirty years).
And most places I have worked FTE expected a work week well in excess of 40 hours; at Microsoft any FTE who put in two successive 40-hour weeks was guaranteed to soon be the subject of an email saying he had “decided to pursue opportunities outside Microsoft,” corpspeak for he had been terminated. At Microsoft they first pushed man-killer work weeks with stock options and catered dinners; later they did it with the Reign of Terror known as the annual review.
Yeah managers suck and they can suck a golf ball through ten meters of garden hose if they come from the business world instead of having actual code experience.
But I would dispute the assumption that the methodologies would be great if they were followed exactly. I offer as evidence that a lot of people who believe that say that pair programming is a good thing and in my mind any manager who orders anyone to pair program deserves to die in prison.