If they had allocated 1k devs into n teams to develop different approaches and review and test each other's code and approach. No, the result would've been a better patch and probably not that piece of hot garbage.
In human organizations, that glue itself gets incredibly complex and expensive, as number of pieces grow.
People are the plywood, fragile, finicky, and useless if left to their own devices. Management is the middle school kid who needs to take the wood he's been given and make something that will hold up to all the weight that'll be put on top it. In order to do this, he's been given a hot glue gun and enough glue to mummify the entire thing if he so chooses. Most of the kids will rush bullheadedly (or should I say uncaringly) into gluing the sticks together into something that "looks like it should work." They use too much glue, the structure isn't optimized for load handling, and when the day of truth comes, it crumbles down when the bucket that's supposed to hold the weight, destroys it!
What is glue? Whatever management wants it to be. It can be a team leader or a hastily configured IRC channel. In my experience (this includes organizing, delegating, and making sure that 40 devs-et-al get what's needed done), if you choose your sticks right, taking the time to make sure they're not hiding any structural faults, you can make the job 65% easier. If you lament that choosing sticks if difficult, I reply with "it's just practice."
The main issue I've seen, has been the all too common "there are no good managers." Especially in technology. The remedies for this? There's no bandaid. Each manager has to realize his personal shortcomings and fix them. But, to throw up his hands and say "the more people working on a project, the slower it'll get done," is a nice way to say "I can't handle all these people, but I'll excuse that away by saying it's inevitable. It's even industry 'common sense!'"
The person who discovers the bug may not come up with the best repro case. The person best equipped at fixing the bug may not be best person to track it. Being able to spool up new people on a problem for cheap keeps the whole experience lower stress and generally improves your consistency with regards to success.
If the cost of someone trying a crazy theory is linear in man-hours and O(1) or even O(log n) for wall clock hours you're going to look like a bunch of professionals instead of a bunch children with pointy sticks.
From what I understand, Microsoft has never gotten there. They got too big to fail a long time ago. And certainly wouldn't have for Windows 7.
Not to mention that the whole problem would most likely leak once that many people knew about it.
It's ultimately a matter of talent, resources, and proper management. Which is hardly an insurmountable problem for a major tech company which decades of experience solving world-is-ending bugs.