Yes, she did, at that one particular time, but think of all the years she was married to Bobby and never once showed the interest or enthusiasm for the oil business enough to ask Bobby to teach her something about the business. That says a lot about how little natural enthusiasm or passion Pam had for learning the oil business. Did she ever even express an interest in taking a few business courses at a nearby college? Not once.I'm rewatching season 7 where Pam is working with Cliff at Barnes-Wentworth. She insists that she wants to really learn the oil business not just be a figurehead.
Then, when she had a sizable amount of her money invested in Cliff's business, then finally, after 7 seasons, she wants to be something more than just a figurehead. She wants to learn enough so that she has at least some idea of how her millions of dollars are being spent. That's distinctly different than had she, from the first season, shown a passionate interest in not just learning the oil business, but becoming great at it. She would have had to become great at it to ever compete with the likes of a JR Ewing, but she didn't have the education or the passion for the business to ever become able to compete at the top level of the Texas oil industry. Even if she had, she might have still found out that while she had the inclination to become great at the oil business, she may not have had the aptitude for it - few people do!
To overcome her lack of education and experience in the oil business, getting a late start in it, Pam would have had to have shown a remarkable natural aptitude for it as well as a great desire to put forth the time and effort required to become great or even good at it. People don't earn MBAs and spend over a hundred thousand dollars in the process because an MBA or at least a BA in Business is just a slight advantage; it's a massive advantage over not having that education. Those people who spend 100or 150 grand on an MBA aren't being foolish - they're doing everything they can to maximize their chances at success. Pam didn't have that drive, that passion, the love of the business needed to become great at it.
Without a Business degree and without a lifetime of experience in the oil industry, the only way it would have been somewhat believable that Pam could have been competitive at the top level of the Texas oil business is is she had both a love of the business (which she did not) and a phenomenal natural aptitude for it. Pam was written as a character with an average intellect. She was not portrayed as having a genius level intellect. There have been people, who literally were geniuses, and succeeded at the top levels of their fields despite having dropped out of high school. Pam was certainly not portrayed as being a genius level character - someone like a Walter White of Breaking Bad who was an amazing chemist. Pam was of a very average intellect, as the character was written.
Given all that, it wouldn't have even been a little bit close to believable for her to quickly learn in two or three years what it took men like JR and Wendell a lifetime in the business to learn. To have Pam being shown as a formidable competitor to the best of the best in the field would have made a mockery of the show. Even if she'd loved the business, gotten a Business degree, and spent her whole adult life in the business, it would have been no guarantee that she'd have become among the best of the best. Everyone earning a Business degree and a genuine love of business aspires to becoming one of the best in their field, and still only a tiny, tiny, percentage of them ever become able to compete at the top level of any field of business. It is that competitive.