I grew up non-observant, while simultanesouly attending MO day school through high school, and eventually ended up “american haredi,” started off learning in kollel and then went to work. I asked myself the same exact question that the original poster brought up—-
“What is the difference between a working Haredi and a working MO- both spend 90% of their waking hours at work, learn a little and go to shul. So whats the difference????
Great Question!
I will tell you the difference.
Out of my class of about 150 in my MO high school, about 20-30 are still “shomer shabbos and shomer kashrus”. How many of them learn torah on a daily basis- maybe 15. Out of 150.
Do Haredi schools have kids going off the derech, sure, a large amount, but nothing close to what is happening at MO schools.
In short, the difference between the MO guy who works and goes to shul is a success story, he is among the top 10% that made it out of the system alive. Having made it out of the system, you are right, there is not SO much which differentiates him from Haredi working.