That, at any rate, is the grim scenario depicted in a report just issued by the London-based International Institute for Strategic Studies (IISS) think tank.
In an annual survey of the main strategic trends during the year, IISS experts say that until Al-Qaeda's bigger plans are ready, it will content itself with striking at "soft targets" in the United States, Europe, and Israel, and aiding the insurgency in Iraq.
The survey asserts that recruitment to the network is accelerating, and that there are now 18,000 "potential terrorists" at large. It refers to the charismatic "drawing power" of elusive Al-Qaeda leader Osama bin Laden, who is presumably still alive.
And the survey says that despite the death or capture of more than half the group's 30 leaders, Al-Qaeda has an effective "middle management" in place around the globe.
The IISS blames the increased severity of the situation in part on the U.S.-led intervention in Iraq. It says Washington has failed to grasp that the 11 September 2001 terror attacks on New York and Washington were a violent reaction to American pre-eminence since the end of the Cold War.
It says the American-led military invasion and occupation of Iraq was designed to advance U.S. strategic and political interests in the Middle East. As such, it ran directly counter to Al-Qaeda's aim to purge the Muslim world of U.S. influence.
As the editor of the IISS strategic survey, Jonathan Stevenson, puts it: "[The war] has actually increased the U.S. military footprint in the Arab world and, of course, in the Muslim world generally, and certainly it was also intended to increase the United States' political influence there."
Accordingly, the survey says, the Iraq intervention was always likely in the short term to increase the motivation for terrorists and recruitment to Al-Qaeda.
But the question arises, how can the IISS survey arrive at the neat figure of some 18,000 potential terrorists around the world?
Stevenson explains this assessment “is based on a rather cautious U.S. intelligence estimate, of 20,000 foreign jihadists who traveled to Afghanistan between 1996 and 2001, and who were indoctrinated and trained in the camps that were run by Al-Qaeda and the Taliban. This figure has been widely quoted to open sources -- but mostly without specific attribution -- since 9/11."
Stevenson says about 2,000 Al-Qaeda members have been killed or captured since 9/11, mainly in Afghanistan. Taking this into consideration, the remaining figure is 18,000.
He says that only a "small number" of those are hard-core terrorists, with a larger number being peripheral support figures, providing logistical, technical, or financial assistance. The remainder might be inactive individuals who are susceptible to Al-Qaeda's agenda, and who might step into active operational roles at any time.
One of the most alarming assertions in the IISS survey is that Al-Qaeda is still looking for capability with weapons of mass destruction (WMD), whether these be nuclear, biological, or chemical.
A WMD expert with Jane's military publishing group, John Eldridge, says there is "every chance" the group will eventually obtain such weapons. Even if it does not, the mere suggestion is itself a powerful tool.
"Just talking about this [WMD] stuff achieves their aim, because it throws people in paroxysms of fear and lack of confidence in the future. So [Al-Qaeda militants] are achieving their aim by doing nothing, in a sense," Eldridge said.
Eldridge says that many of the chemicals and toxic materials that are possible to use for chemical or biological weapons, or in a "dirty" bomb, are readily available everywhere.
But Eldridge cautions against exaggerated fears, saying that, for instance, the terror attacks in the United States using deadly anthrax brought only a handful of deaths. He says the true impact of the attack lay elsewhere.
"The impact on the American psyche, if you like to call it that, was just out of all proportion, so it wasn't so much a weapon of mass destruction as a 'weapon of mass disruption,'" Eldridge said.
But the difficulty of predicting what Al-Qaeda will do is compounded by the loose structure of the movement, in which many groups may take their agenda from bin Laden, but are not under any hierarchical control.
Dublin-based terrorism expert Shaun Boyne says, however, that events have shown they can coordinate their activities.
"They [can] carry out these coordinated attacks, like we saw in the [March bombings] in Madrid, and obviously in the 9/11 attacks, and also in the [earlier] embassy attacks in Africa," Boyne said.
Boyne says some attacks have clues leading back to bin Laden, others do not, and an exact estimation of the movement's powers of coordination is not possible.