Disagree: the roads are packed, the hotels are packed, airlines raise prices a lot, and there's nothing you can do about it if you're forced to go then. I've always taken my vacations in July or September and remained in Padova during August, which is great - it's empty and has a relaxed, easy going feel which is absent during the rest of the year.
Also, if you're running a company that for some reason wants to stay open (by, say, letting your employees choose their own vacation time and having them not all go at once), you might still have a hard time of it because your suppliers and clients are all closed too.
Long vacations are good, but I don't care so much for the mass exodus in August.
Yes, but less so than closing the company down for a month.
I think it's pretty obvious that in a workplace where each member adds more than a constant value, the latter is favorable.
Edit: woah, I can't respond to your post, probably to prevent those back-and-forth chains. But you're right, it's only obvious in a simplified model of a workplace I had in my head when writing it. In real life, nothing is obvious :)
Staying open conserves momentum and provides some continuity.
By having a shutdown, people are encouraged to use up their PTO. If you don't have enough PTO, however, then it is effectively unpaid leave.
Although I am usually encouraged to take at least part of my time off on the Christmas/NY break (which is Summer for us obviously).