People accept that deal when they have a very strong guarantee that their $100 will still be worth $100 at the end of the term. Combining the low yields of bonds (let's be honest, your numbers are chosen for their roundness, not their realism) with the low safety of stocks is the worst of both worlds.
There's quite literally a word for low growth but reliable stocks that pay out decent dividends. "Value stocks", as opposed to "Growth stocks" where investors expect to see the returns directly in the stock price.
