I guess I still don't get finance. How are these companies in such massive debt and I guess not out of business? Like why is the stock price not closer to zero?
For a simple way to look at it.
For every company, Assets = Liabilities (debt is a liability) + Equity.
AT&T has $547bn of assets. Their debt is approximately $157bn (total liabilities, or claims against the company, including debt, amounts to $353bn). So if you subtract their liabilities from their assets, the remaining portion $194bn, is book equity. So AT&T, despite having a lot of debt, has enough assets that there is still value in the company (equity) after all of the liabilities are considered.
So that's a simple way to look at it.
Now with regards to debt. $160bn is a lot! But you have to look at a few things when speaking about a company's amount of debt. It's leverage (total amount of debt / company's earnings), interest expense and free cash flow (how much cash a company can generate to pay down debt after all other uses are paid for).
AT&T earnings (EBITDA) are about $60bn. So it's leverage (debt/EBITDA) will be around 2.5x by year end. That's actually not terrible. Disney because of the acquisition of Fox is closer to 3x, I believe.
It generates roughly $30-$40bn of free cash flow per year, so it can afford to pay the interest on its debt as well as paydown debt as well.
AT&T, Verizon, Comcast and Charter can afford to service their debt because their cash flows are generally stable. If a recession hits, people still need their cell service and ISP.