I don't think for some people it's as easy as "just leave". I'm now retired (early) and if I wanted to retrain or take up a casual job, I could. I have really no restraints (I currently look after my granddaughter full time but they'd have to find an alternative if I wanted to go back to work) , I now have the time to retrain and I could also take a casual contract on minium wage because I can afford to do that.
But it wasn't always this way. I've stayed in jobs because the money was paying our mortgage. I've stayed in jobs because the benefits at the time were what I needed. I've stayed in jobs because coming out of them ,meant I was only likely to get a temporary contract, and I couldn't do that with a family relying on me. I couldn't afford to retrain and start on the bottom wage again, let alone all the schmoozing that comes with a new job. I had a family at home who relied on my money and also my hours. I worked in teaching so I could predominantly have the longer school holidays off with my children. I couldn't go and retrain as a doctor, lawyer, chef whatever because I didn't have anyone to look after my then small family.
It's easy to say just leave, but it all has to add up, all the factors have to right. Of course, if you can afford to leave and have the support infrastructure, go for it. I just couldn't.
Then take out the money and benefits, some people are in minium wage jobs with neither the money or any benefits and they still stay because there is little alternative. It's hard getting a job these days on minium wage, a lot of people are chasing them. It could be that your minium wage is still highly needed for your family or giving the right hours,circumstances or commute.
I'd love to tell people if it's not the right road for you, start paving another, but I don't believe it's just a case of "get up and leave ". I've wanted to leave my job so many times but it was a very selfish thing for me to do.