The 270 was " popularised " in the USA by marketing experts and gun writers....including his Royal Highness Jack Oconnor.
" Poularity" does not necessarliy translate in to greatness.
Many cartridges are great , but not necessarily sold in huge numbers.
The cartridge has a reputation well beyond what is deserves. As previously stated its not terrible, nor is it fantastic...its just the child of a marketing company who "invented " something different at a time when inovation was needed and the market was sucked in to buying it. At least the US market.

Its interesting to note that arguably the greatest sporting rifle ever built up the end of 1946 was not chambered in this " popular " cartridge. Yes, thats correct there is a huge hunting and shooting community outside of America.
ts called the rest of the world.

Mauser already had a line up of truly great cartridges including the truely great 7x57 for which they designed and built an intermediate length action which was and still is truely and deservedly famous.
Americas answer was a one size fits all Model 54, and later the pre 64 ( a crude copy of the real thing) in the " popular" ( at least in the US), 270Win. Americans flocked to it like the model T Ford.
This dedication to the 270 almost exclusively by the US is further emphasised by the Great English makers that even today consider chambering in such a " thing" to be sacrilege.
I dont think Hollands , or Purdey for example chambered many 270s...yes they undoubtley did, but Oh my goodness...really Sir!
Did they " retail" Model 54 Winchesters in 270.....nope, instead they chose Original Mausers and Mannlichers.

I dont believe that any other cartridge evokes so much discussion, even by people who have never owned , or hunted with one.
Its not fantastically efficient, you may even argue its overbore...its not one thing or another, but its very common.
Some cant even explain why they dont like it, and many , many people don't. Its bordering on tasteless.
Strange, I dont seem to see any negative comment on the venerable 7x57.