I saw them do it a few years ago, it would link to the relevant clip in the youtube video that you could watch directly in the search results

They do this already. Some google search results will present a snippet of a Youtube video most relevant. Here's an example of a search query with such a snippet.

https://imgur.com/a/bxiBYUO

Here's an example: https://www.google.com/search?hl=en&q=youtube%20replace%20fu...