Garen,
The above quote is either untrue or misleading, depending on ones interpretation of the word "possibilities".
Firstly, those who get a PhD in highly theoretical (and non-computational) areas of physics often find the opposite is true - the possibilities are limited, sometimes completely. Often they are lucky to get a temporary postdoc position, and employment outside academia (or education) is almost impossible. Tales of these people running off to wall-street to become quants were spawned by the stock market boom of the 90's. It still happens today, but not much, and certainly not enough to be considered a career option.
Secondly, even those with a PhD in highly applicable areas of physics (magnetism, semiconductors, etc) have very limited options. Of course, they don't necessarily have a hard time finding a job. Those jobs pay very well and can lead to a great career. But make no mistake, those jobs are with a select few companies. Whether the "possibilities" are endless is an interesting question - one can certainly be hired at any number of retail outlets with the degree. However, we can say without hesitation that opportunities in science are not endless.
None of this is to suggest you shouldn't get a degree in physics. I'm generally happy with mine (my career outlook seems reasonably good). Physics is a difficult degree that teaches a wide set of powerful skills. It is entirely possible for one to get the degree and end up very employable. However, it is also entirely possible to spend 11 years in school and find oneself biting and clawing for a poor paying temporary position. The difference is largely planning.
I should also note that similar statements can be said about many other degrees, including engineering, law and medicine.
Whatever you choose to do, play a tight game or suffer the consequences.