Having driven the 4cyl Sierra (Test Mule), I actually liked it. I would not buy it, but I liked it..
That being said, Scotty is still one of the biggest idiots on YouTube.
I'm not a Scotty fan, either - anything of his has to be carefully picked apart for one possible nugget of actually useful / correct info. But - he's got 2.3 million subs to his channel. 2.3 MM people (or bots) who actually look for and watch his videos.
According to sites that track that kind of thing, that means he's making a minimum of $126K a year from YT alone (and he's got other revenue sources, like Amazon.) Acting the fool pays, I suppose.
Back to the 4cyl Silverado... it's not something that I could ever use. But - there are enough people who could make a 4cyl work for them, that it'll help with GMs CAFE numbers.
With Tesla starting to push (hype) their upcoming "F150 killer", it appears to me that V8-equipped trucks are going to start getting rarer over the next 10yrs. You'll still be able to get one - but you'll pay dearly for it (as if they're not charging outrageous prices for them now).