2800% is a much bigger number than 83%. But if you do the math using your numbers, you see that GE substantially underperformed the S&P since 1981:

GE = (1+2800%)*(1-83%) = 4.93 = 393% appreciation since 1981.

S&P = S&P has appreciated 2000% since 1981.

GE << S&P

To be fair, most companies underperform s&p 500. S&p is driven by giant winners, and every generation has different winners. In the 90s GE was the winner and other companies in s&p trailed them. This is what makes survivors like Microsoft so amazing, they managed to remain on top by reinventing themselves many times under different leaderships.

Maybe that's why Welch said to measure against GE's future leaders if they are destined to forever underperform the S&P. :)