Edit: OK, I see what you mean. Unified feed across ALL channels you're subscribed to. That's not what I'm using.
Also, there's a good reason for subscribing to channels: it actually help the channel creator because the subscriber number (which is what that number is) feeds into their algorithms regarding reach.
Oh wait, you can't, because there hasn't been one for ages now. They only have per-channel and per-playlist feeds.