This is often the problem I have with people who would like us to see PhD as a general purpose but just higher degree. Degrees can be a process of ranking people or a way of educating them. I fear we are losing the battle against ranking as a purpose at high-school and undergrad, but not yet PhD.
However, some of what you sa in the specifics y isn't quite true for the British system. The biggest difference is that there is a 4 year limit. This means you must submit by 4 years at the latest irrespective of whether anyone thinks you are ready.
Consequently the viva/defense is a real exam that takes place in private and is performed by two examiners, at least one of which must be from a different uni. People can and do fail. Outright failure is rare, but being asked to go away and redo parts (within a time limit) is very common.
Finally, while entry to government funded doctoral training programs is fiercely competitive, if you can fund yourself (about £30k a year) entry usually is down only to the judgement of the supervisor.
Having now read the original article, why does it not surprise me that this guy is a fan of IQ, thinks its an important measure of someones worth, and that an IQ of 125 is not anything to write home about?
Also, how can you argue that you are against credentialism, and then argue that you want the credential to mean something again?