The logic is perfectly sound, as it does not consider the needs of only one specific individual.
Also, I never said that one was preferable to the other- they are simply options.
Some have the money to pay upfront, get the job, and be able to move on whenever they like. Others don't, and can therefore be trapped by a bond.
It all comes down to your individual circumstances. Horses for courses, and all that. If you only consider career advancement, buying a type rating can either be very good (as it was for quite a few 757 drivers a few years ago) or very bad (if you got sucked into the BMI "type rating with a job at the end... er ... maybe" scam of the mid-nineties).
I am completely against paying for type ratings, and bonds in all their forms. Other industries train people to do the job, spending tens of thousands on them, and never even the hint of a bond. So it should be in our business.
However, I also recognise the economic realities- which means that bonds are probably here to stay (subject to a possible EU legal challenge), and that type ratings will always sell whilst there are those rich enough (or with daddies rich enough) to pay for them.
And that, folks, is the way the world is. Choose your individual morality, and take your stand accordingly.