Marandahir
Crown-Forester (he/him)
If you look at it this literally, your statement makes sense. Unfortunately your statement applies to a huge number of things in D&D like who can fire four arrows from a longbow accurately in six seconds. Who could swing accurately three times with a great axe in six seconds. Who could fire a heavy crossbow accurately multiple times in six seconds. Then there is spells. So kind of pointless to apply that kind of logic to raging.
Rounds are more flexible than per day. I could see someone raging for a round. Ever a watch a strong man competition? Some of those Scandinavian folk "rage" or get jacked up to lift something for a few seconds. What's the difference between that a guy getting jacked up to swing his sword hard for a few blows, then go back to normal? Absolutely nothing.
A fighter can only swing an axe three times within six seconds at high levels – it's quite easy to swing an axe once in that time period, or even fire off two arrows within that time. When a fighter or other warrior class gets a second attack, it's a super power.
Rage is also a super-power, but you're talking about being able to constantly switch in and out of emotions. With a character that is about uncontrollable emotion. That doesn't make sense, at least not at low levels. Maybe as a high level feature (like how a Wizard can turn spells into cantrips).