I think you're missing some context, the reason that the booths were light was because the booths are there as an introduction to the company or a quick faq. There were meeting rooms set aside to do real business across the street (in the room that held the expo floor last year) not to mention all the hotel conference room meetings that traditionally happen. Hitting up a big platform owner's booth and striking up a deal is pretty rare, generally your business people call their business people and schedule a meeting away from the noise of the convention and then talk about what ever needs discussing.
And while there was a large advertising, cloud (database & server), and analytics contingent there was also the usual motion capture vendors (real time, facial, etc), middleware (AI, procedural textures, procedural cities, particle editors), content out-sourcers (animations, audio, 2D animation, cut scenes) and a few engines (unity, havok, corona, marmalade, etc). I had to make several passes over the show floor before I felt confident that I hadn't missed anything interesting. It's easy to tune out the booths that were just there to accept resumes or representing schools, the harder part is to notice the booth that just happens to be next to something interesting. Every time I walked by the oculus rift booth my attention was drawn to the video of people playing hawken instead of what ever booth happened to be adjacent to the oculus rift's booth.