Plenty of people do, many more than are in that server -- I asked some of my former coworkers and none knew about it, but we all spent a whole lot of hours tuning CUDA kernels together :). You have one perspective on this sector, but it's not the only one!

Some example motivations:

- Strange synchronization/coherency requirements

- Working with new hardware / new strategies that Nvidia&co haven't fine-tuned yet

- Just wanting to squeeze out some extra performance