We're going to be in Afghanistan long term. This is way past Bin Laden at this point. Lots of problems in the region that aren't going away in our lifetimes. We will always be able to use the "instability" of the Afghan gov't as a justification to be there. Afghanistan is too strategic with everything going on in the region. Permanent presence there allows us to project firepower quickly where necessary.
Even if we wanted to leave the country would quickly destabilize and breed many more Bin Ladens. Another issue of major concern is the stability of Pakistan's nuclear weapons. We've seen Pakistan's government isn't exactly on rock solid ground either.
To your conspiracy theory, it definitely isn't outside the realm of possibility. Or another conspiracy theory is that he's already dead and these "tapes" that occasionally surface are fakes created by us.
from wiki:
As of July 2008, hundreds of millions of dollars were being spent on permanent infrastructure for foreign military bases in Afghanistan, including a budget of $780-million to further develop the infrastructure at just the
Kandahar Air Field base, described as "a walled, multicultural military city that houses some 13,000 troops from 17 different countries - the kind of place where you can eat at a Dutch chain restaurant alongside soldiers from the Royal Netherlands Army."
[181] The
Bagram Air Base, run by the U.S. military, was also expanding according to military officials, with the U.S military buying land from Afghan locals in different places for further expansion of the base.
[181]
As of January 2009, the U.S. had begun work on $1.6 billion of new, permanent military installations at
Kandahar.
[182]
In February 2009,
The Times reported that the U.S. will build two huge new military bases in southern Afghanistan.
[183] One will be built in
Kandahar province near the
Helmand border, at
Maiwand - a place famous as the site of the
destruction of a British army during the
Second Anglo-Afghan War. The other new U.S. military base will be built in
Zabul, a province now largely controlled by the Taliban and criminal gangs.
[183]
Geo-strategic military build-up
The dramatic build-up of an indefinite American/American-led military presence in Afghanistan has unsettled some regional powers, including Russia. However Russia has agreed to let the United States and NATO to use its airspace for logistical purposes
[181]
"Is it all to fight a number of Taliban - 10,000, 12,000 Taliban?" Zamir Kabulov, Russia's ambassador to Kabul, has questioned. "Maybe this infrastructure, military infrastructure, [is] not only for internal purposes but for regional also."
[181]
Russia views the large and indefinite military build-up as a potential threat "because Afghanistan's geographical location is a very strategic one," Kabulov said. "It's very close to three main world basins of hydrocarbons: Persian Gulf, Caspian Sea, Central Asia."
[181]
Other observers have also noted that through a stronger military presence in Afghanistan, the U.S. may be seeking to strengthen its own position in the region to counter increasingly warm relations among India, China and Russia.
[180]
Along with its proximity to the vast Central Asian and
Caspian Sea energy sources and being in the midsts of the regional powers of India, China, and Russia, Afghanistan also holds strategic significance given its border with Iran.
[179][184]