Anecdotal point: I have the exact same Acer Chromebook 11 that the OP mentions in the article, which I bought for around $150 USD. It all feels like plastic, but has been very durable for me.

Case in point: I was assaulted and robbed last year walking on the street, while carrying this laptop in my backpack. I don't have much else in the backpack and it's a thin one without padded protection. The robber pistol-whipped me and I fell to the ground. He kicked me in the back once (while I have the backpack on). My Chromebook took most of the force. There is still a visible dent on the front cover of the laptop right now, as a result of this. It still works perfectly (other than the dent being an aesthetic issue). This was a year ago and I am still using this Chromebook.

I also had none of the issues you mentioned with keyboard switches, power adapter plugs, etc. Maybe it's a manufacturer thing and not a Chromebook thing? Maybe Acer is better?