Absolutely right. It isn't a contest between liberal arts and STEM: it is about building diverse, critical, integrated teams instead of technology monocultures. Communication, writing, and sociological insight are crucial _additions_ to a hardcore STEM team. As a CTO with an MFA, I can tell you for certain that my arts background has been the key to my success building product cultures and finding the best viable technology paths. But it doesn't mean it is the only way. Also: read lots of novels. They help you become a better human whatever your degree.
I completely agree. So much of engineering is actually about understanding the problem, so adding more people from the same background will not improve this. I always hire a diverse set of people, and help them work together as a team. While it is crucial to have some solid CS people there, having humanities (especially Library Science, my favorite degree to hire from) helps cut through the groupthink and improves the solution pool, same as hiring both young and old programmers etc. Also, its more fun.
You can totally get a great job with only technical training, but those "bullshit lib arts requirements" are exactly what will allow all of your colleagues to advance past you. Literature and art are not just "fun": they are part of becoming rich human beings. Others' ability to speak well, and connect with, write to, and understand others will turn them into your bosses fairly quickly. But if you want a good job, and to stay there forever, technical training is absolutely sufficient.