It was my observation that back then the born-in Witnesses were socially stunted, weird and uneducated with the mentality of people in a small town who refuse to accept the newcomers and who suffered from serious envy over people who looked prosperous and had some education.
There are also 2 categories of born-ins. One group is everything you described (including a serious case of "holier-than-thou"). This first group are the ones love-bombing the new recruits and creating the next generation of born-ins. I've heard some pretty mean things said about the new converts they're actively love bombing. Don't be fooled - even members of the first group often have a double life.
The 2nd group typically leaves the JWs or are mentally out. They break every rule they can without getting caught (education, socialization, etc...) - the art of the double life. The push to baptize at a really young age is probably due to this second group. A lot of born-ins wouldn't choose baptism once in their mid-teens.