You are wrong assuming all workouts need to be at MAP [emphasis mine].
So you know how we (cyclists, triathletes, etc) base some intervals off of FTP (sweetspot, threshold, over-unders, etc.)? Most of those are not done at FTP…they are based off of FTP. “Off of” really just means they are close in terms of percentage.
The nomenclature of “maximum aerobic power” misleads us into “power at VO2max” thinking, which is not a thing. You want to ride at a given power AND duration (BOTH!) that elicits the state of maximal oxygen uptake (a physiological response). The “about 5 min power” part is what is supposed to help you construct a set of intervals that will elicit the state at which maximal volume of oxygen is taken in, delivered to and consumed by working muscles (i.e. VO2max). Why so wordy? Because ppl say and think “VO2max power” all the time and it’s meaningless. It confuses a metabolic state with a mechanical state.
A bunch ppl can and will respond with all manner of how you figure out whether you’re doing the intervals the right way and which ones to do in the first place to drive aerobic capacity. Hard start, slow component, “all out”, panting, “i just feel it, bro”, “I use WKO5”, “my coach tells me”, “TR labeled them as VO2max”, etc. All that is great and there is more than one way to skin it. But you have to understand the above first.
Actual answer:
MAP gives you a number to test against after doing a block of training, and it can give you an anchor against which to construct zones (because for many ppl it happens to be about 5 min power).