In the grand tradition of "what could have been," Bespoke Investment Group offered a blog post yesterday showing what the Dow Jones Industrial Average would look like today if Apple (Nasdaq: AAPL), rather than Cisco (Nasdaq: CSCO), had been added when General Motors (NYSE: GM) was pulled in mid-2009.

As Bespoke points out, the issue at hand isn't whether it was advisable to replace an industrial company like GM with a tech company, but rather whether Cisco was the right tech company to get the nod. While Cisco's products provide the backbone for the oh-so-important Internet, Apple's gadgets have made their way into an insane portion of U.S. households and are changing the face of technology.

In other words, there's a solid argument either way. But what would be very different in the hypothetical world of "Apple in the Dow" is the level of the Dow today. At the time of Bespoke's analysis, the (real) Dow was at 11,725, but the research firm calculated that with Apple in the mix instead of Cisco, we'd currently be at 12,805 -- or almost 10% higher (you can find a chart comparing the two Dows on Bespoke's blog).

My takeaway from this is something that's been said many times before, but is something that I don't think can be repeated enough -- at least until something changes. And that is that it's silly to rely on the Dow as a reliable indicator of the health of the U.S. stock market and economy. Tune into most mainstream stock market reports and you hear "Dow this," "Dow that," and "When will the Dow hit 20,000?" Who cares?

At one point in time, 30 stocks may have been adequately representative of the overall U.S. stock market, but I don't think there's any way that can be argued today. As Bespoke's analysis shows, the swap of a single issue for another would give us a significantly different picture as painted by the Dow. And that's not to mention the fact that while we're looking at this index as a measure of the U.S., many of the companies in the index -- such as McDonald's (NYSE: MCD), Intel (Nasdaq: INTC), and ExxonMobil (NYSE: XOM) -- do as much or more of their business outside of the U.S.

The bottom line? If you're looking for a true measure of the U.S. markets, skip the Dow.

General Motors and Intel are Motley Fool Inside Value recommendations. Apple is a Motley Fool Stock Advisor pick. Motley Fool Options has recommended buying calls on Intel. The Fool owns shares of Apple and ExxonMobil. Motley Fool Alpha owns shares of Cisco Systems. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.

Fool contributor Matt Koppenheffer owns shares of Intel and McDonald's. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.