I just tried to think like, I take a loan of 10k with 20k BTC down for a year.

At the end of the year, I owe say 11.5k and my Bitcoin is worth 25k. Do I take out a second loan with 23k BTC to repay the old one and reclaim more Bitcoin? I'd have to have a hell of a lot of Bitcoin to buy a year's worth of fiat and roll it over with less Bitcoin in collateral ever year. 4 years worth of Bitcoin to keep the scheme going.