Um, maybe they didn't have to do presentations and such, but I'm sure there were still people with SA. I don't think its a modern disorder. Technically, since our society is more immersed and surrounded by people all the time, all the exposure should have lessened the amount of SA. I would think someone who was used to staying in with the family all the time, would have no idea how to act when faced with someone new. I could see it being very difficult for them. The longer I stay as a recluse in my house with just my family, the harder it is to socialize with people out of the house.
But of course they wouldn't have seen it as a mental disorder, just as shyness. Which I'm sure was hard because people would just tell them to 'be a man and get over it'. On the bright side, I'm sure it was easier for women. Wasn't it more accepted if women and girls were reserved and modest, you know, without opinions even? Today, even though its less embarressing for a girl to have SA, we are still expected to socialize all the time.