I'm not sure if they'd be borderline retarded, but the point stands. As long as you're working and providing for your family, does it matter if you're not the sharpest tool in the box?
No, not really.
One definition of intelligence is making choices and doing whatever brings you toward your long term goal in life - and if you're satisfied with working and providing for your family then you're set. A lack of intelligence may however prove it difficult to achieve whatever goal you'd like to achieve. Some argue that happiness is the ultimate currency and while it seems plausible I wouldn't be comfortable making such a statement for certain.
It is, but I'll bet there are a lot more rich and successful average IQ people than intelligent ones (largely due to the music industry and sports!) Some people have a good grasp of business, without any other natural academic flair, and are able to make a good living for themselves. Builders don't tend to be geniuses, but I don't think I've ever met one who was short on money. Being intelligent doesn't equate to being successful, there are too many other factors at play. I run my own company, but I wouldn't class myself as being successful, not yet anyway. Maybe one day I will be, but there's a lot of time and effort that needs to go into it first, nothing to do with intelligence.
Of course there's more successful men of average IQ than highly intelligent ones and the obvious reason for that is that there are way more "average" men than highly intelligent ones... and also the fact that the world is tailored to suit the common man in a lot of situations - your scenario with builders is actually a very good example, at least here in Sweden where we got all sorts of tax laws that redistribute money to the building sector. And sure, there are a lot of different factors that come into play when determining success, in individual cases. Intelligence and self discipline are two of, if not the, most important factors when determining success in a more general perspective, at least according the science I've taken note of.
Only to a certain level. I still believe that anything over 150 IQ leads to almost being on a different plane to everyone else, and they find it hard to join in with social settings. They can maybe teach themselves how to do so over time, but it's still very automated and not natural.
Sure, it can be hard for a highly intelligent man to socialize with someone of average intelligence but who's to say that it's the highly intelligent man that's acting "weird"... Do you get what I'm aiming at? You can only judge the situation by your own (limited) perception.
A discrepancy of roughly 30 IQ points, which is what separates the borderline retarded from the average and also what's separetes the average man from the highly intelligent one, is not a small step but a giant leap. I think that most people feel most comfortable among peers but the problem of being highly intelligent is that you don't have a lot of peers...
Socializing tend to become awkward when it's not fullfilling and humor is a great example of this. A joke, however clever it might be, is just "weird" for someone that doesn't get the funny... and we all know how it goes when trying to explain it.
For whatever it's worth, I won't respond to any replies that's adressed to all the crap that I just wrote. I'm too tired... and also too Swedish.