This WSJ article is the most convincing case yet for the idea that al Qaeda is severely degraded:

Hunted by U.S. drones, beset by money problems and finding it tougher to lure young Arabs to the bleak mountains of Pakistan, al Qaeda is seeing its role shrink there and in Afghanistan, according to intelligence reports and Pakistani and U.S. officials. Conversations intercepted by the U.S. show al Qaeda fighters complaining of shortages of weapons, clothing and, in some cases, food. The number of foreign fighters in Afghanistan appears to be declining, U.S. military officials say.

The Journal supports other reporting which finds that our campaign of aerial drone strikes has decimated the group. At first blush, that seems a fine argument for the Biden approach to Afghanistan. The problem comes if you think that, without a major U.S. troop presence, the Taliban could take control of substantial parts of Afghanistan and offer al Qaeda a haven in which to reconstitute. And it's not at all clear that we could collect the necessary intelligence to continue effective strikes without thousands of our boots on the ground.