Osama bin Laden; Mullah Mohammad Omar; Their Focus during This Period
Osama bin Laden during this time had very little to do with the Taliban. He was almost assuredly funneling some operational funds to them, but other commanders in his operation handled that.
Bin Laden himself had "bigger fish to fry."
It is important to understand the focus of these two men and their operations. Mullah Mohammad Omar, the supreme leader of the Taliban, had no visible interest in establishing the caliphate. He was obviously not opposed to the idea of being a devout and committed Muslim, but his principal focus was Afghanistan. There is no indication that Omar was unintelligent, but few would attempt to argue that he was "worldly." Omar and the Taliban were ("are" in the case of the Taliban) a classic example of a regional/domestic terror organization. In short, they couldn't care less what happened outside the nation of Afghanistan. Of course, all this changed to a degree after 9/11, but even today, at the writing of this text, the existing Taliban organization and leadership are not interested in what happens outside the country as long as their "national goals and interests" remain intact and unmolested.
Al Qaeda and Osama bin Laden, on the other hand, were/are the polar opposite. Bin Laden's desire to establish an Islamic state (caliphate), in which whole world was converted to Islam and the world's people were governed by shariah, was very obviously an international goal and effort.
Bin Laden proceeded with this effort as Omar did with his, and the two men rarely interacted.
In hindsight, however, it is likely that Omar didn't want to be too closely connected to Al Qaeda. Some would contend that he always knew bin Laden was going to bring down a hammer on him and his household at some point in the future. Bin Laden's effort to construct a safe haven in the base of the mountain outside Omar's compound south of Kandahar (discussed and illustrated earlier in this text) was very obviously an attempt to mitigate any concerns Omar had. Bin Laden was likely counting on Omar's ignorance of logical reactions on the part of the United States to the Al Qaeda operations. He knew that the United States wouldn't let a mountain fortress keep them from capturing or killing Omar and probably him as well, once he launched more ambitious operations, but Omar probably did not foresee this. The cave complex was little more than a "feel-good" measure.
As the Taliban continued in its effort to take total control of the country, bin Laden continued in his effort to fund and coordinate future Al Qaeda operations, and Zarqawi continued recruiting and training operatives and fighters for Al Qaeda, at his complex in northwest Afghanistan, outside Herat.