Short Termism just an urban legend
Most of the projects that I have worked on that failed were, in my humble opinion, hopelessly overstaffed, over engineered and over there (i.e. had a whole bunch of cultural issues to contend with due to having large number of expat consultants).
My other contention is that teams of no more than 5 people work well, larger teams fail spectacularly.
I was recently dismayed to find that the 7, plus or minus 2 rule for the number of things we can retain in short term memory was just an Urban Legend. I always thought that might be an explanation of the small team size success factor.
I still think it's a good guide, and the maximum project/company size then pans out at around 3906 people. For a project, I would suggest it is a couple of orders below that, at around 156 people. If you have a bunch of very smart people then you could use 6 or 7 as the base number, but in my experience you're only as strong as the weakest link, and just because they're smart doesn't mean there won't be problems!
Think about it, is it possible for a CEO to know exactly what the key issues and resolutions are for each of the business areas if there are more than 5-7 of them? Is it possible for a Project Manager to understand each team's responsibilities and status if there are more than 7 teams reporting to them?
The size of a company or project could be categorised by the band in which they fall, each size of company would require different levels of support infrastructure to keep it functioning efficiently.
So, the bands would be 1, 6, 31, 156, 781, 3906.
Where a set of tasks are very well defined then team sizes can be larger (e.g. checkout operators), but going beyond 9 people will probably lead to fragmentation of the 'team' into 'sub-teams'. That may not be an issue, but where team goals are concerned, it probably is.
Anyway, I think what I'm saying is, don't have more than 5 people in a team unless you have very clearly defined tasks, and even then, don't have more than 9 unless you plan on barking out orders and expect blind obedience.
But it's all Urban Legend, and there's no inherent limit on our capacity to deal with multiple things simultaneously....

