No, but they also wouldn't be that effective at taxing wealthy people that would structure their wealth to avoid the tax. That's the issue. You either lower the limit to the point where you capture the upper middle class, or you don't get any revenue because wealthy people can avoid the tax entirely.
Yeah, exactly: The floor is not going to be "100 million" for very long before they have to drop it to "100 thousand" because the people with "100 million" can change the way they structure their wealth faster than the regulators, because of regulatory capture and they'll need that money from somewhere. The upper-middle class carries almost the entire tax burden of the U.S. It's hard to boo-hoo about when you've got 2 cars, a single family home, etc. but it has an enormous negative impact on the economy to punish one tier of the economic ladder so hard.