Why do people not lose the game on 15-20 second chases? What even is good chase time

I'm at a point where I have no idea on what's considered a good chase. As far as the duration. I thought 15, 20, 30 second chases were good. But in my survivor games, this seems to be nowhere near long enough.

Which I find actually strange because on killer, if I don't have sub 15 second chases, so 7-15, I'll probably lose that game. If I average 15s on a survivor in my killer game, I lose a 3 gen. Let's calculate that really. 15s to down, you have to pick up, and carry to a hook. Another 5-10 second process. I then have to walk all the way back, because the survivor was smart and ran me furthest away from the gen that needed to be worked on. So the walking back process adds 10-15. You're looking at bare minimum for all that, 30-40 seconds for doing my objective if the chase was 15 seconds. During that time, the survivors can on comms, immediately jump on the gen with perks and toolboxes and break an important gen. Meanwhile I see streamers play, have 20-30 second chases and the game immediately isn't over somehow.

Yet when I play survivor, 15-30 second chases is a stomp of that match still. I'm favor of the killer. And that's being generous because the average survivor I usually see go down In... 7-10 seconds?

It just blows my mind how what I consider to be too long a chase on killer, is a short chase when I'm playing survivor. Obviously the factor is gen efficiency, comms. But idk. I just don't like how I'm the only one that gets punished for a 15 second chases. Some ppl chase for 20-30s and don't get entire gens popped somehow. Because if the chase was 30s, that means you have to pick up, carry to a hook, walk back. Adding at least 15-20 extra essentially an entire minute. And when multiple ppl hop on a gen with stuff that help do gens faster or just perfect timing, I just can't have a post 15 second chase. Even 15s is kinda scuffed.

Idk. I feel like if the killer took 20s to down me, the game should be over but it's not somehow at least when I'm on survivor lol. Just the imbalance of swf. If I chase for 20s per survivor I lose that game. If survivors get downed in 20s when I'm on survivor, we lose.