Earlier quoted context omitted.
"We expect to see profit driven to zero in a competitive market, and that is what we saw in Standard Oil's pricing." We don't see that in any of the information you provided. You gave a graph of oil prices, not of Standard Oil's profits.
I was responding specifically to the latter portion of the quote excerpted by the grandparent post, which indicated minimal and zero profits for Standard Oil in areas with competition, in alignment with economic theory which indicates economic profit tends toward zero with increased competition.
You're choosing to laser focus in on a specific aspect of the story and cut the bigger picture out of the frame in a very telling way.
Surely you've considered why Standard Oil's decision to do this was found to be anticompetitive, have you not?