My grandpa would agree, I think. DOS is way easier to teach by rote, and is a much more consistent experience than a modern operating system.
Simpler for what it does? It's an unfair comparison. You could say that walking is simpler than flying, but that's not true if you're trying to get from New York to Beijing.
That is still true if you are trying to get from New York to Beijing. There is waaaay more chance that something will break in your ability to fly to Beijing than in your ability to walk there.
What? No, you would drown if you tried to walk there. I'd say that's about as broken as it gets. What are you talking about?
You clearly never tried setting up packet based TCP/IP on a network of DOS computers utilising multiple brands (and in the case of 3com, different chipsets) of network cards.