So they definitely over leverage their assets, but you can't just make an LLC and get a loan to buy a house. You either need to bring in outside capital or personally co-sign the loan. Once you get cash flow and assets in the LLC name you can start getting loans subject to underwriting requirements. Additionally, if you plunder the LLC you risk inviting an attempt to "pierce the corporate veil" which can make you financially liable for debts owed by your business is you under-capitalized the business.

However for most large corporate real estate holdings, they have likely been in operation for years and regardless of how big or small their debt load, they probably would have some sort of crisis with a industry wide collapse of property values.

Which is fine. Make them into affordable housing. But the owners aren't walking away without taking a financial hit.