They're able to get the high end customers, and this strategy works because they can sell the high end customers high end parts in volume without having to have a good software stack; at the high end, the customers are willing to put in the effort to make their code work on hardware that is better in dollars/watts/availability or whatever it is that's giving AMD inroads into the supercomputing market. They can't sell low end customers on GPU compute without having a stack that works, and somebody who has a small GPU compute workload may not be willing or able to adapt their software to make it work on an AMD card even if the AMD card would be a better choice if they could make it work.