> If you composed a portfolio of high dividend, stable, stocks... Could you theoretically have a "guaranteed" monthly income AND the ability to liquidate, in the event of an emergency?

No. You can buy an annuity, or US Treasury bonds, but guaranteed high returns don't exist, and adding in a liquidity requirement doesn't help.

Note that GM declared bankruptcy in 2009. Even if it is still "too big to fail," that doesn't mean investors can't lose all their money.