An unfair comparison since YouTube probably has more servers, money and sense that most people so doesn’t care about any scale problems that migth occur as they just throw money servers at it and doesn’t care about the cost.
It’s also limited to only providing one topic. (New Videos on a channel)
Not the many topics that Twitch offers.
Twitter has been changing how this work and the current API is pretty limited in comparison (in my opinion) to the older one (without paying for Twitter API access).
The current offering limits you heavily to the types of data you can get and the number of people you can get that from. So Twitter has the same issues.