Bleh that is always annoying, and do keep in mind that these things are often tiered. You might still have to deal with state and local. Consider in the situation of a small business you typically have to be deal with local taxes, sales tax with whatever state agency, and federal. It's quite annoying.
I don't know that anyone has modeled this out with reasonable data.
That was something I glossed over before. If you make more, you spend more. You actually spend a lower percentage of income though. It is more likely to be a tax cut for the guys who don't really need it, although I'm not sure how it would work out at the extreme levels. There are other factors such as whether it would apply to commercial real estate. Consumption taxes are typically not modeled against investments of any kind. They are modeled against purchases by end users. It has to be that way because you would otherwise kill businesses that rely on slim margins (wholesalers come to mind) and introduce weird accounting into certain types of accrual.
You clearly don't live in California, given your theoretical housing prices.
That is an important point. Many things sound good when they are unexamined. As for writing off their entire house, I would have to see actual paperwork. I can link you to the
IRS pages on business use of your home if you like. It goes by square footage of the area used if and only if it is used solely for business. They can also disallow this if for a variety of weird reasons. I don't know where you got this idea, but it's unlikely that the person who claimed that would hold up under audit.