Oh, please.
Those ports have undergone substantial capacity enhancements in the last 6 years -- mainly aimed at accommodating precisely that import market you've identified (the Alameda Corridor project is a good example of this).
Obviously not expanding fast enough to accommodate all the ChiCom ships bringing in Chinese craps. Get with the program Alberta! So now Mexico (land of the NAFTA maquiladora) will become import middleman, bringing in all kinds of Chinese craps for you to buy.
China --->>
Mexico--->>
Kansas City ---->> Mexican customs in KC --->>>
And then onward to Wal-Mart and Home Depot.
This is why the Mexico ports issue discussed here and the Trans-Texas Corridors initiative go hand-in-hand . . . because even the most efficient ports in the world are only as good as their inland infrastructure allows them to be.