I worked in a startup in the B2B space a while back, and it's amazing how much big customers can push you around and demand features. The salesguys would promise something and then a week later we'd have the feature in a special patch build for them. I heard Cisco did the same thing, and by the time they got big they had hundreds of special branches for different groups of customers. It was a mess.

Then I worked for a couple of big B2B companies (currently work for one) and it's basically the same thing except that two weeks becomes 6 months. But given how small the market is, you are still doing customization to drive deals. I think a big part of the appeal of developing these frameworks is so your own support staff can add the feature in without changing the core code. I'd imagine this would be the case for all the big B2B players. No way do any of these companies survive just selling off the shelf, and I have some admiration for the support guys that parachute into Penn State or the Foo Department of Bar or Nestle and help manage a whole massive deployment or roll out some brand new feature. They are working nights and weekends and I'm sure there's a lot of good war stories there.