But according to the chart there could be 500 or more S&P points before the top. you're leaving money on the table!

The question is how deep will the crash be. If the S&P goes up those 500 points and then crashes by 300 you are better off staying in. OTOH, if the S&P goes up those 500 points and then crashes by 5000 (I didn't bother looking up the value, so I don't know if that is possible) you are not out much by getting out today.