I'm not missing the point, I never said the .303 is under powered. Whether it was over powered is a matter of opinion.
As recent developments in the mid east have shown theres still a place for the main battle cartridges.
The intermediate cartridges have often fallen short on todays battle fields, and would not have been a good choice for most of the fighting of WW2.
The Assault Rifle is a jacked up SMG when it comes down to it.
In the more open battle fields of mountain ranges and in dense forest and jungle foliage the Main Battle cartridge is king.
The intermediate cartridges often can't penetrate common urban barriers for that matter.
The LMG in 7.62 and the Designated Marksman Rifle in 7.62 must take up the slack.