I agree with you, but you can't do it for everything.
I see so many people just throwing money away it's crazy.
Like you said, cooking for yourself and your family. Don't eat out. Bring packed lunches to work. My family might get fast food once or twice a month max, the rest is all from the grocery store. Eating out is stupid expensive now.
When it comes to your cars. Learn to change your own oil, battery, and air filter. Dealers and repair shops charge stupid prices for this stuff and it's easy enough to do that you can do it in 15-30 minutes yourself. Remember to properly dispose of your fluids.
Learn to fix your own tech, tech jobs pay a lot which means that you as the customer will pay a lot to get your shit fixed.
Learn how to fix simple plumbing in your house, repair drywall, install/repair simple electrical stuff. When I see people in my local area paying handymen $500 to install a ceiling fan (not the electrical part like running wires, just hanging the damn thing), I about lose it.
I'm still shocked to this day that police weren't mowing people down as they tried to force their way in. By not doing so, they basically said, "this is fine" IMO.