With the unemployment rate so low and the number of jobs created increasing, why would disability application be a logical next step?

I am not an expert but from what I have read after a few years people drop off the unemployment numbers and aren't counted anymore. They pretty much cease to exist as far as the employment world goes. Either they have to go on welfare or disability.

People only drop off the unemployment numbers and stop being counted if they stop actively looking for work.

https://www.bls.gov/cps/cps_htgm.htm#unemployed

Even people who no longer appear in the official U-3 unemployment statistic will often appear in U-4/U-5/U-6 depending on their exact circumstances.

https://www.bls.gov/news.release/empsit.t15.htm

rconti posted some interesting links above:

https://www.theatlantic.com/business/archive/2013/03/disabil...

http://apps.npr.org/unfit-for-work/