Correct. Flavor is an important component of taste and the eating experience. Temperature is a separate component. They are weakly linked, but with the temperature I envision for fresh McDonald's fries left on a tray for 15 minutes before serving the customer, there is no meaningful difference to me in flavor. The change in temperature is obvious, but as I don't value it much in my own eating experience, I have difficulty imagining its importance for others.

In my mouth, flavor is the dominant component. Temperature only matters if the food has fats or volatiles with a phase transition temperature between 25 and 40 degC. If food is too hot, I taste burning heat instead of flavor, and when it's too cold, the ice crystals numb my taste buds. But in between, my perception of the flavor is more affected by chemical composition than temperature. Room-temperature french fries are fine. You can chew them up without burning your mouth. Refrigerated fries aren't quite as good, because the fats solidify and the flavoring volatiles don't vaporize as readily. So pop them in the microwave, and they're good again.

Depends on how you use the microwave and moisture content. But, 5 minutes at 20% is significantly different than 1 minute at 100%.