It depends on the circumstances and how willing the airline is to help. When Delta canceled my next-morning LGA-FLL departure during a snowstorm, and the best option was rebooking BWI-ATL-PBI, and they were pleasant about it, I didn't go after them for the bus fare to Baltimore or the Tri-Rail to Fort Lauderdale. But in example (a) above, if I'd paid a baggage fee or been forced to gate-check a bag I normally carry on, I'd have put them on the hook at the 20:01 mark. I wouldn't complain about nonfunctional wi-fi as I see it as a "nice to have" (even when it's advertised and perhaps swayed my decision to fly with that airline, such as JetBlue). Other inflight problems I'd deal with case by case, but generally if I arrive within a reasonable time and having received reasonable service for my ticketed cabin, I wouldn't bother.
Seth