Why was dogfighting a thing?

[Admiral Beez]

From what I understand, the narrower definition of dogfighting means aircraft trying to out-turn each other and getting behind the opponent to shoot him down. For this, maneuverability is paramount. In WWII, aircraft designed for this were to my knowledge repeatedly defeated by aircraft focusing on speed instead of agility and using boom-and-zoom tactics and "energy management".

I think I get this, with the faster aircraft, you go in fast on the enemy, make a strafing pass and get out before he can retaliate, that is basically the idea right? But what I don't understan, why was maneuver-focussed dogfighting ever a thing then? How was it in WWI? The triplanes sacrificed speed for agility, why weren't they dispatched by less maneuverable but faster aircraft using such tactics?

IMO, the IJN's fighter pilots should have focused less on the thrill of dogfighting and more on fleet defence. If you shoot down a trio of Wildcats but one Dauntless puts a bomb into your carrier, your dogfighting just cost you a carrier.

A carrier's fighter wing has two purposes.... destroy/stop enemy strike aircraft from hitting your carrier; and, protect your own strike aircraft so they can hit the enemy's carrier. In the first instance, the defending fighters should avoid dogfighting with the enemy's escorts, but instead attack the strike aircraft.