What if it did happen literally and symbolically? Jesus ascended from the Mount of Olives (Acts 1:12), but before that, He stood there often, teaching, weeping, and pronouncing judgment on Jerusalem (Luke 19:41-44, Matthew 24). There's even a well-worn footpath still visible today, testifying that His feet did indeed stand there.

The splitting of the mountain represents the opening of a way of escape (Luke 21:21). His presence brought judgment on the Old Covenant and salvation for the faithful remnant.

So yes, Zechariah 14:4-5 was fulfilled literally, spiritually, and historically, just like so much prophecy.

Why do so many still believe He will return and stand on the Mount of Olives?

Because they ignore the time statements and treat apocalyptic language like it's GPS prophecy. Zechariah 14 uses symbolic imagery to describe the judgment and deliverance that took place in the first century. Jesus already stood on the Mount of Olives, physically, repeatedly and even ascended from there (Acts 1:12). The mountain splitting is symbolic of a path of escape for believers, just like He told them in Luke 21:21, "flee to the mountains."

They expect a future event because they misunderstand the nature of His return, it was not to set foot on dirt again, but to bring judgment against apostate Jerusalem, just as He said in Matthew 24:34, "this generation will not pass away until all these things take place."

The idea of a future return to a literal mountain comes from reading prophetic poetry like it's a weather forecast, instead of seeing its fulfillment in covenantal judgment and kingdom transition.