Taking Cuban's argument to its logical extreme, nothing can ever be guaranteed because a large asteroid could hit the earth and kill us all. I'm more likely to believe that Amazon.com will honor its service guarantees than I am some no-name ecommerce company, and Amazon's guarantee is close enough to certainty that I don't question it. The probability of a promise being kept is somewhere between zero and one. Our job as buyers is to estimate that probability accurately enough to make rational decisions.
Wow. With all the fraud and corruption that is being revealed to exist in our financial/political system this, THIS, is what author gets worked up about?
Items like this make be believe a little more in disinformation conspiracies. That this post exists to give people something to talk/think about other than what "they" are really doing.
Fixed-income investments are not good with respect to inflation. A thousand / month withdrawal when someone is 65 might not have the same buying power if they live to 85. Another case of if it sounds too good to be true, it generally is.
This ceases to be true if we enter a deflationary environment, as is reflected in the stock prices of annuity-issuing companies.