Cpus have hit their limits and not growing. Software has stagnated and recycles concepts from 50 years ago, and not growing. What's left to study? Either world-scale clouds or the growing field of NNs. Out of the two i 'd pick the 2nd cause it's either more fun or more unpredictable. Students are making a rational choice
Even if those fields completely stagnated, there's great progress to be made in high performance computing, security, bioinformatics, and human computer interaction (just to name a few).
