What "incubator culture" factors are critical to the success of a business incubator (or co-work environment)?

What are the "ecosystem" or "incubator culture" factors that are critical to the success* of a business incubator (besides the obvious technical services like high speed internet).

For example, how many people in the incubator, activities at the incubator, etc.

*Success : large percentage of businesses that are incubated for a reasonable period ( 6 months or so) that become profitable (either through revenue or through Venture Capital) within that period.

Every incubator should have at least one resident who actually achieved something, better said has a successful start-up experience. Mainly because fresh entrepreneurs need someone who can assist (or, better, mentor ) them with priceless first hand knowledge, but can also be some sort of an idol and motivator to anyone who is willing to succeed through start-up.

Incubators should also host as many competent individuals as possible for the same reason stated before. There is an incubator in my area which is somewhat recognisable but its problem is, that its ran by professors (who graduated somewhere in 1980 and since then they've been teaching only) from business school who have never really worked in any company not to mention their lack (zero) of experience with modern start-ups. On the other hand, incubator has nice rooms, fast internet, is able to potentially get some financing, but still has no notable results for past few years

So main thing incubators need are individuals possessing suitable experience and skills, ability to produce critical opinions and ability to connect different areas of knowledge which is needed to succeed.