Well yes. A big reason why youtube has changed so much is infact because of them.
For those that didn't know already youtube was bought up by google a few years back, and that was actually when the changes started to take place. Just take a quick look on how you must link your youtube account to a google account nowadays whether you want it or not.
Whilst the old youtube were based around fresh ideas and fun, the google youtube is more about business and earning money. Sponsored channels get more views, there's ads everywhere, star rating system removed and you cannot see the rating on videos when looking on related list anymore. You know, such things.