Why would you pay someone when we already have a mechanism in place here to pick up additional people for free? See http://www.slug-lines.com/ for more information.
Edit: Didn't notice the comment below, that's what I get for not refreshing the page...
I think a major portion of their revenue model was based on classes. This isn't necessarily a bad thing, but it does box out members who have a lot of skills in a particular area from sharing that knowledge in some sort of structured way. For example, it might have been more engaging to members to set up a recurring event such as "machining monday" or something where people interested in a topic could gather and either share experience and knowledge or at least help each other figure things out. Instead, they focused on classes that were $40 - $600 a pop. They also had a hard time retaining instructors that had professional experience. When the shop I was a member of first opened, they had a lot of instructors that were working part time at the shop and worked full time in a related field (machining, woodworking, etc.). Over time those instructors slowly drifted away and were replaced with younger and less experienced staff. It is a little difficult to learn a complex skill like welding from someone who has only been doing it for a few months and cant really offer any knowledge outside of the packet provided with the class.
I recognize that there needs to be some sort of minimum knowledge needed to operate a machine safely and think that the class model isn't a bad method for that goal. However, I think the problem is when your revenue model depends on people continuing to take more advanced classes which is difficult to sustain.
The "birds of a feather" type meetings would be one way to further member engagement, get people interested and gain the confidence to use the tools, and wouldn't have cost much if anything for the shop to implement.
I think another issue that TechShop had that I am not sure other makerspaces have to deal with is the conflict between people that ran businesses out of the location vs. casual or hobby members. There were a lot of occasions where a small (3-4) member company would reserve a particular tool for an entire day (sometimes multiple days) and box out the casual users. I don't know the best method to combat that, perhaps you can limit the number of reservations an individual or group of individuals can make in a month, or shorten the reservation times in the evenings. Maybe it would have made sense to structure the memberships differently and charge less for a nights and weekends membership than a daytime membership or something. I can say that it was frustrating as a user who showed up a few times a month to see people that camped out on a particular table or area of the shop and not being able to find space to work on my projects or get time on the machines.
Edit: Didn't notice the comment below, that's what I get for not refreshing the page...