That the simulator is a complete crap shoot. Ignore the numbers, ignore the salaries, ignore the park attributes. You'll have just as good of chance closing your eyes and rolling the dice. Seriously.
I know, I know. Wah, wah, and wah.
Why do I say this? A 1907 George Winter, with an ERA of 2.07 and ERA+ of 123 gives up 10 earned runs in just 6 innings, in a pitchers park. Open League.
Ridiculous. Again, you'll have just as much luck closing your eyes and selecting players completely at random. No, I don't expect to win every game, and I know the obvious answers, but I don't expect players to depart so severely from their real life performances. I mean, what's the point of pouring over the stats then if the randomness of the simulator offsets any possibility of expected performance?
And don't sit there and tell me all your pitchers behave as expected. Because they don't, and you know they don't. So don't bother.