I never "Landscaped" in the 80's-90's, but sure did cut a LOT of grass!
While not the increase I would expect (given inflation on other goods/services), I pretty much tripled what i charge to mow a lawn now, vs in the mid 80's.
Thing is, now I have much more efficient equipment. Things like string trimmers and blowers were just coming available. The ZTR didn't exist. Belt drive WB's weren't really a common item. It was tractors and some Yazoo 3 wheel riders that dominated the scene.
Funny when I think back to the mid 80's and the equipment we used lol. I had John Deere tractors and a 3 wheel J.D. front mount deck mower. Now I have Wright Standers and JD Pro Ztrack mowers that just kick azz. It's all about the equipment for being productive nowadays.