Well, the way the dude presents himself is a turn off to me, but listening to the video above, he had more maturity than I expected. I am a little beyond the the author tube at this point, meaning I have seen so many youtube videos on writing that they all blur together for me now. I could not disagree with anything this dude said. I am not aiming at getting picked up by a publishing house, but I do want a quality product and I hope I delivered one with my first book. I'd listen to other videos from him...but dude...stop pulling on your beard. Its distracting.
And while I am at it, Tim Pool...same for you. Stop pulling on your misfitting jacket. Take your game up a notch and lose the nervous body language.
This is just for my process, but I like to go over and reread some of the writing guides that I've touched on for decades. I find it keeps me from wandering too far into left field and getting lost in my own head. It keeps the fundamentals front and center. I like to say "writers write, that's the only rule." All else is process.
He's not wrong, but somehow I feel like he isn't completely right.
What I mean is that the reasons he mentioned are all correct. However, they get you rejections because they're a symptom of bad writing, not because of the specific reason. Except maybe the wordcount one. Some wordcounts are just an auto-reject, just because of that.
But the others simply come down to if you write an amazing book then you have a much better chance at being offered a book deal. If you want to see this for yourself, pick 2 novels. One should be one of your favorite novels (preferably recently published), while the other should be an indie-published book with an Amazon sales rank in the millions or unranked (feel free to pick one of mine, I can take it...). Compare the opening page.
The differences should be obvious. And they all come down to the writing in one being better than the other. That's not to say the indie one will be bad. It can still be a decent story and well worth a read. However, it will lack the traits of a professional story teller in the same way that by listening to two musicians you can easily tell the concert pianist from the enthousiastic hobby musician. It will simply be less good. (note that I don't mean all indie books are bad, some are as good or better than trad-published ones. Just that most of the ones that aren't selling are probably worse...)
Simply removing all adverbs from your story wont automatically make it better. Doing it purposefully might. However, even if you have no adverbs in your first chapter, that doesn't mean the story will automatically be considered worth publishing.