The 30-06 comes from the 30-03, which was made and designed around the 7x57 Mauser and its success. The 9.3x62 is derived from the 8x57, which came from the 7x57. I did not say it was made from the 30-06, that's why I quoted the 7x57, and stated the 9.3x62 is the best of the bunch.
The 9.3x62 came out before the 30-06. It is not a coincidence that the 30-06 is almost exactly a necked down 9.3x62 case. Most of the high pressure, successful cartridges if that time were all stealing one another's ideas and Designs and using the same case, or basically the same case.
There are very few truly Unique cartridges not using a parent case in some way that were successful. And it makes sense, it's much easier to use a existing case and change its dimensions and test it.