Ya may want to re-check the ballistic tables for the 150 gr .270 and the 150 gr .30-06. Reload manuals and tables from various ammo makers show nearly same velocity for both. With certain hand loads there can be differences of up to 150 ft/sec between them. I agree that the .30-06 has more potential for a bit more powder and a bit higher velocity due to the shorter bullet of the 150 gr .30-06, but they are usually the same velocity when loaded.
You'll get the same energy transfere when you throw the same grain, shape, and velocity of bullet regardless of bullet diameter. The difference in these situations is sectional density.
With reloading you certainly can make a 150gr 270 shoot with a 150gr 30-06. What you can't do is make it keep up when you go after the heaviest loads. Not possible because of the bore size. You'll notice in cartridges with the same parent case that the larger the bore size, the lower the pressure at a given charge. The difference isn't great but exists. where the advantage goes to the 270 with the 150gr bullet is that it is a heavier constructed bullet with better ballistic qualities. Those ballistic qualities exist because of the length of equal length bullets. You'll find the same is true with all cartridges based on the same parent case. The bigger bore reduces the pressure somewhat.
You'll notice that the 130gr bullet in each has about 100fps advantage in the 30-06. The 270 is generally said to reach 3200 fps and may well be able to but then the 30-06 will do 3300 fps if pushed. In either case, pressure must be suspect. The same 130gr bullet from a 25-06, wildcat bullet's, won't get 3100fps without a very long barrel and high pressure.
keep in mind that, all things being equal, as bullet dia increases, pressure decreases.