Exxon is a special type of company.
It was one of the largest, most-profitable companies in the world 100 years ago (then known as Standard Oil).
Exxon is still one of the largest and most-profitable companies in the world today.
And, given that many of their existing oilfields will continue producing for the next 100 years, Exxon is likely to still be one of the most-profitable and largest companies in the world long after we are all gone.
The same is true of the oil industry. The oil industry was one of the largest and most profitable industries in the world long before we were all born. It is still one of the worlds largest and most profitable industries today. And it will still be so long after we are all gone.
Interesting fact: many oilfields in the San Joaquin basin of Southern California have been producing oil since the 1890's. Continuously.
It's hard to think of many industries where the risk-capital that you invest today will still be paying dividends 100 years from now.