The 2mm/employee cutoff is an interesting insight. Sidenote - is that what the grey line in http://blog.joshlaurito.com/wp-content/uploads/2013/10/Scree... is supposed to represent? It wasn't fully clear to me.
Is there anything actionable that you found? This all seemed to me to be interesting but non-actionable to a founder.
>I assumed that software companies would be more scalable and generate more revenue per employee, but the numbers don’t bear this out.
Any chance that's a bias from your data? Software companies can span the gamut from startup that's optimizing for their monthly-active-user-count to enterprise-software firm that's established with a high margin and low capex.
Also, a little discussion around why you used log-log graphs would have been welcomed by me.