Same here. The amount of money I've saved over my lifetime doing DIY things is enormous.I also think a lot of the problem is also people just will quickly pay the money than do a little research and fix the small problems themselves. I'm no HVAC tech, but I've replaced contacts, three capacitors and my air handler's fan relay board. None or these require that much know how, but probably saved $1000s in labor and parts.
I see the same thing in the plumbing field. I know plumbers who are so busy that they will now ghost customers with small leaks because they are making bank from changing out toilet valves. A pressure regulator could cost somewhere between $300-400 for a plumber to fix for a $70 part and a little sweat. This is in semi-rural Alabama, not the bigger cities which imagine nail people much worse.
The most recent money saver was diagnosing, removing, having the ABS module repaired rather than replaced, and reinstalling it myself in my Ford truck. $140 Total for the repair versus $1100 just for the part at the Ford dealership.
I replaced the capacitor in my upstairs AC unit last year. I ordered the part from Amazon at 1in the morning and had the part on my front porch before I finished my coffee.