When I say YouTube took a downturn after money was introduced, I mean in terms of content. I'm definitely for content creators getting paid for their work, but one of the problems with YouTube is that they've always rewarded the "wrong" content creators. I use quotation marks because it's subjective.
But the algorithms of YouTube rewards quantity over quality, like if you post a video every day, you're more likely to be featured in the related section etc. Do you remember the reply girls? Absolutely worthless content, but they flooded the site because they got rewarded for it. YouTube actually did something about that situation though.
The best channels, with the best content has a tendency to not get the exposure they deserve IMO. One of the reasons I like DTube is because there are no hidden algorithms so it's a leveled playing field.