A team of one also cannot have multiple experts gathering to solve a particular problem, where their combined set of expert knowledge matches the problem best. The one person must be a jack of all trades, and necessary a master of only a few, due to humans' limited lifespan.
(I'd say it's a bit like a multi-threaded program: very often one thread is not enough, but only a few threads can do varied but coordinated tasks. Massive multiprocessing only works when coordination between peer threads is not required, and usually they do the same embarrassingly parallelizable thing anyway.)
Additionally, a team of one has no redundancy. You know, how Bob is responsible for maintaining the business critical databases, and now the databases are on fire and Bob is on a canoe tour through Canada without a phone. Oops.
For business critical things, you generally want 3 guys who can replace each other competently. Three, because one is none if the one guy gets sick, and two is also one if the other is on vacation and thus none.
You jest, but we've had weeks during which - out of 6 people - one was on vacation, two were sick, and then two more had to call in child-sick because their respective day cares had to close due to positive covid tests. And suddenly you're last man standing between the outage gremlins and customer systems.
A team of one has zero coordination overhead.
A team of one also cannot have multiple experts gathering to solve a particular problem, where their combined set of expert knowledge matches the problem best. The one person must be a jack of all trades, and necessary a master of only a few, due to humans' limited lifespan.
(I'd say it's a bit like a multi-threaded program: very often one thread is not enough, but only a few threads can do varied but coordinated tasks. Massive multiprocessing only works when coordination between peer threads is not required, and usually they do the same embarrassingly parallelizable thing anyway.)