I agree with this, although the same logic could be applied to SQ. Then again, they are the least integrated member of *A, so maybe there is some truth there.

The basic reason that these types of airlines are threatening to other alliance members is they have built an entire business around connecting international traffic through their hub. While people do use them to reach their destinations (eg DXB or AUH) many more use them for connections. Therefore EK, for example, competes head to head with the likes of CO and UA for N. America traffic to India, Pakistan, many Middle Eastern countries, Australia, NZ, etc. With one flight out of JFK, they can offer relatively easy connections to dozens of first and second tier cities for anyone in NYC. Yes it's a one-stop service through DXB, AUH, etc. but they make the process easy and price their fares to make them attractive.

For a US airline (or EU airlines like LH, BA, etc) they will be limited to focusing much more on the larger cities from their home markets.

As an example, look at the range of destinations that EK flies to in India and Pakistan from DXB - these are ideally suited to connecting traffic.