"Borrowing money" and "paying cash" are very different.Yes, but in today's world of near zero interest, it is only the powerful and connected players (large banks and corporations) that can take advantage of low interest rates, giving them an unfair advantage in terms of securing loans to create more productive assets for themselves.
For example, Blackstone purchased billions of dollars worth of real estate following the housing crash. They were able to borrow money at less than 1% and pay cash, something the regular Joe could not do. So the system as it now functions tends to make the wealthy even wealthier.
Regardless, Blackstone didn't force anyone to sell anything. There was a willing buyer and a willing seller. Yes, some people have more money than others. Some use it wisely, and others, like the very connected Lehman Brothers, lose it all. I bet Blackstone purchased discounted real estate from companies that were also "connected" and extremely over leveraged when the economy tanked.