Is having the initiative a fundamental advantage?

Agree with everything you just said qutie strongly: I especially agree with how looking at how there is no inherent advantage to iniative helps you realize that the EV created by iniative is purely a product of the opponents misplay; primarily their ineptitude to play 'correctly' against your hand range.

EG; this includes stuff like calling with KQ on an ace high flop with the right pot odds and a wide enough raising range; or even raising it; given that the raisers range isn't actually that likely to have an ace, even though them taking the iniative may suggest they do).

An example of exploiting iniative I have used frequently is against a fairly tight player we play 3 handed with who 3 bets a fairly normal range but if you cap preflop he will give up overcards on the flop for fear of domination; hence the extra small bet invested causes your opponent to make a large post flop play error because said opponent has not thought about how he is being exploited; he is a victim of iniative, a man made concept that does not actually exist in a game theory model, but only in the minds of the blissfully ignorant.