What you find in each congregation can vary widely. Some congs. A) are in areas with lots of educated professionals with high paying jobs and thus many of the JWs have similar jobs/skills including elders; while other congs. B) are made up of mostly middle income people or lower income/education.
The change in the demographics of the global WT organization during the last 20-30+ years are really the most supportive of this thread (and the comments in the WT).
Including things like:
1) Most members have little education and the education they do have is poor quality or little effort expended since org. says, not important;
2) Low incomes with some in poverty or scrapping by month-to-month (in fairness this could be said of 90% of people today);
3) Extremely low standard for anyone that is appointed or given responsibility in the cong.;
4) Those that do get baptized through recruitment (not born in) are largely impoverished, uneducated and in many cases people that have significant problems in their lives.
With few productive or "efficient" people coming in that can contribute to the success and growth of the organization - you are left with a larger and larger number of takers.
Over the last 50 years, the WT leadership has cultivated exactly this outcome through messaging and policy within the org. An educated person that has been in the org. for the last 50 years (as i have) can easily take a look at all of this and realize the org. is going to continue to shrink out of existence.