I'm not going to vouch for Google's search results - we all know they are declining. Even so, if everyone is using Google to search reddit, that doesn't tell me that google is losing its search dominance. It tells me that even as people try to get away from it, they still use it as much as ever and by that usage are likely helping Google figure out which use cases they need to develop to improve their products.
Also, the idea that reddit will replace it seems unlikely to me. As much as there is decent content on reddit, it exists side-by-side with junk, jokes, trolling, memes, shills, and straight up misinformation. This doesn't stop people from using and enjoying reddit - much of the silliness is all in good fun, but it will become a serious barrier to trying to become the search engine for online content.
Also, the idea that reddit will replace it seems unlikely to me. As much as there is decent content on reddit, it exists side-by-side with junk, jokes, trolling, memes, shills, and straight up misinformation. This doesn't stop people from using and enjoying reddit - much of the silliness is all in good fun, but it will become a serious barrier to trying to become the search engine for online content.