I'd be suspicious of anything that article says since Texas isn't even mentioned as needing a Non-CDL Class A license.
Texas requires a Class A Non Commercial driver license for combined weight over 26,000. To get that license you must take and pass a written test, then a driving test in the rig (truck and fifth wheel, etc.) - not just a truck or car.
Basically - In Texas, a Non-CDL Class A license is required if you drive a combination of vehicles with a Gross Combination Weight Rating (GCWR) of 26,001 pounds or more, and the towed vehicle has a Gross Vehicle Weight Rating (GVWR) exceeding 10,000 pounds. This is frequently required for heavy RVs, fifth wheels, and large horse trailers.
Most people don't know or ignore this requirement, but an attorney once told me without the proper license, if you're involved in an accident EVEN IF IT ISN'T YOUR FAULT, an opposing attorney or law enforcement could press the issue and find that you are basically driving with an invalid license and therefore could be held liable for all damages. Insurance could also refuse to pay, according to him.
I got my Class A Non-CDL back when I pulled a fifth wheel that was over 16,000 pounds with a dually rated at 10,000+. Although we no longer have a dually or pull that heavy of a trailer...I maintain that Class A just in case it is needed. There's no extra cost for maintaining it over a standard Class B license in Texas.
And yes, it's valid in every state across the U.S.