How do they afford lavish personal lifestyle if they're declaring no income (I get the cap gains part, I don't get the mansions, parties, cars, food etc. Bit)
You know Warren Buffett eats McDonald’s, right? A lavish personal lifestyle is not a requirement for being wealthy.
But in general, I assume that most of the perks of that wealth are really attached to the ownership/management of the corporation that produced the wealth.
It's not necessarily that they're declaring no income, it's that their income is entirely composed of long term capital gains which are taxed at a lower rate than standard income tax.
Even without that loophole there are probably a bunch of tricks their financial planners have to minimise taxes (e.g. using trusts/charities, various tax free allowances).
Or alternatively, because they essentially get to defer taxes for as long as they like (by refinancing the loan), it means they have the full tax free amount of cash available up front to buy more wealth generating assets.
It seems to me that quite a few things that we think of as lifestyle, can get written off as business expenses. Not that I know anything about this world.
read the propublica article - it explains. or be lazy. loans ;) in particular low interest loans. as high interest loans would sort of ruin the plot and those are reserved for the working class.