There are in fact 2 rebuttals here, one being the econ 101 answer: If I find out that a large company is gobbling up homes for any price I set on them, then I m

There are in fact 2 rebuttals here, one being the econ 101 answer: If I find out that a large company is gobbling up homes for any price I set on them, then I might as well build way more homes in that area because I've got a guaranteed buyer. That argument can still be overruled in the short term by pointing at the current zoning laws of many countries worldwide, and the second rebuttal is more interesting anyway: Who said anything about a 'reasonable' price? The proportionality constant between the tax levied and the listed sales price of the home is a precise instrument. We could just as easily set it to 0.1% per annum, so that people who list their homes for $1m/year still only pay $1000/year in tax and likely never see a serious purchaser, as we could set it to 10% per annum, where a $1m/year house accrues a whopping $100,000/year in Harberger taxes, which leads to people lowering the listed price, WLT many more sales and purchases, WLT considerably more housing liquidity. You could use either tactic to put the squeeze on bad actors, depending on your goals.