What is it with modern frontend development that people think you can just quickly "get up-to-speed" with it? Nobody would accept these complaints of complexity had you said "I'm just trying to get these web developers up-to-speed hacking on the linux kernel", they would advise you to start them on something simpler, to get to learn the languages and tools gradually.

I agree there's more complexity than there should be, but you also dump them in the most complex stack that can be dreamed up in the field.