LTL type work moving materials and wheeled equipment on 40' equipment trailers with a chauffeur/commercial chauffeur and then grand fathered to a class A CDL when they became mandatory. I don't do that work anymore but I still have a 4x4 and a 2wd truck.
I had five one ton DRW trucks and all were 4x4. A 2wd truck wouldn't get around pulling a 20k Gn trailer on a muddy construction worksite. They also carried my TC's and pulled my RV trailers.
I haven't found a 4x4 truck to have any more maintenance issues or mpg differences than other 2wd trucks I've owned.
I never pay any attention to what other owner/operators are using. They have their priorities as one size don't fit all here.