Well straight away there is a problem with this article - a problem that, I suspect, plagues many such articles.
"18:19 - the last exchange between the pilots and air traffic control -- three minutes later the automatic position reporting system, the transponder, stops working [over the South China Sea].
18:22 - The last primary radar return providing a verifiable “fix” of the 777’s direction is made -- the airplane is flying northwest above the Straits of Malacca.
.
.
.
"
That's some flying. The direct path distance distance between the two points is approximately 850Km. So the direct path (i.e. minimum) speed between 18:19 and 18:22 would be 17,000Km/H. So, plainly, this article has not been proof read.
Having said that, on the balance of probabilities, but having no real data, I support the equipment failure hypothesis.