Really depends on the area. Around here there's not to no money in flooring unless you've got volume through a builder. There's so many immigrants and illegals doing flooring here that they get paid next to nothing. Same with framers, roofers, and masons. You'd probably get a 1/3 of those prices around here doing flooring.
Plumbing, electrical, and HVAC are good money here.
Cabinet installers can make bank if they get in with the right companies and imo I see a lot of builders going back to subbing it out in the next fewyears. A lot of them have gone factory direct over the last 10 years or so. Was good for a while, but all the cabinet direct programs pay like absolute shit now so the quality has severely declined. My warranty guy used to make more money doing side warranty work for our main supplier than he did working for us, but they started dropping the pay on everything severely a couple years ago and got down to about 20% of what they used to pay. I know every client we've lost to direct programs has seriously regretted it and frankly my company sucks.