"I dont magic myself a raise because income tax goes up. It works the same for landlords. If supply and demand remains unchanged, prices remain unchanged."

What you're missing is that the market floor get universally pushed up. There's no competition from cheaper places because they all increased their rent to cover the new coat so they can still make their same margin. The demand is still there because people still need a place to live.

"The only change I could forsee to affect either is previously empty properties being put up for rent"

Any numbers on that, or are you just going to keep claiming it's a big enough vacant supply to significantly affect prices?

"They'd really love for that to be how it works and sometimes they pretend it is."

This is still tied to the previous comment. If the number of vacancies are not sufficient, then supply is adequately constrained to just increase the prices to cover costs. Because, again, this increase moves the market floor.