I agree, most personality traits can be aquired, even if they are heavily selected against genetically. But it isn't always desirable to do so, even if these habits are considered socially useful.
For instance, I'm naturally a night person, but I developed through self discipline, over the course of holding down a standard 9-5 job, a habit of 'early rising', even on weekends. This had, over a period of time, a seriously negative effect on my health and cognitive ability. Switching to a job that allowed me to revert to a more natural sleep cycle was a much better solution for me and my employers.
It's important to do a cost-benefit analysis when attempting to change behaviour, sometimes a change of environment is more feasible.
Um, isn't the knowledge of many spurious arguments and no strong ones over a period of time weak evidence that no better argument exists (or at least, has currently been discovered?)
I do agree with the second part of your post about argument matching, though. The problem becomes even more serious when it is often not an argument against X from someone who takes the position, but a strawman argument they have been taught by others for the specific purposes of matching up more sophisticated arguments to.
Well, I was specifically thinking of this passage
Which, to my admittedly rusty knowledge of mid 20th century philosophy, sounds extremely similar to the anti-metaphysics position of Carnap circa 1950. His work on Ramsey sentences, if I recall, was an attempt to reduce mixed statements including theoretical concepts ("appleness") to a statement consisting purely of Logical and Observational Terms. I'm fairly sure I saw something very similar to your writings in his late work regarding Modal Logic, but I'm clearly going to have to dig up the specific passage.