Rational self-interest

Economists believe that people are (mostly) optimizing individuals, and most of the time we also believe that companies are profit-maximizing entities. Three examples of how useful these assumptions are:

1. George Will writes that Toyota "sell[s] its hybrid without significant, if any, profit and sustain[s] this practice... by selling about twice as many of the gas-thirsty pickup trucks that the president thinks are destroying the planet." Now, it seems like we have three options here. Option #1 is to think that Toyota is a profit-maximizing entity... in which case why would they sell the Prius for little or no profit? Option #2 is to think that Toyota is a hippie-dippie company concerned about the planet... in which case why would they sell all those pickup trucks? Option #3 is to conclude that George Will is making stuff up. I certainly don't know the bottom line about Toyota's profits, but I will confess that I have almost zero confidence in George Will. (See e.g., this lousy column about global warming, where his interpretation of this data is that "there has been no recorded global warming for more than a decade.")
   
2. A new book claims that Alex Rodriguez was "tipping pitches to friends on other teams", i.e., cheating. This strikes me as almost ludicrous: economists don't believe in conspiracy theories, which is why we think competition (e.g., in the cell phone market) will result in lower prices. And you're telling me that A-Rod had a (presumably large) collection of friends on other teams with whom he conspired until now without anybody finding out? I don't buy it.
3. Now, steroid use in baseball: whether Manny Ramirez did or didn't, that's something that makes sense from the perspective of individual self-interest, even if it doesn't from the perspective of the group as a whole.