I think it's also important that HN doesn't have infinite scrolling. It's old-school: 30 items per page, click at the bottom to go to the next page.
I made a rule for myself that I would never go past page 2 of HN. So, each morning, I see 60 items, and if none of them interest me, then I just move on with my day. I think that's why I never became addicted.
The rate at which content ends up on the front page is also slower than your ability to consume it. So even if you do keep clicking, you end up on yesterday's links you've already read.
If you didn’t have that rule would you go past page 2? Frankly I just don’t find HN articles as cheaply and quickly mentally palatable as other sites. The content here is usually more cognitively demanding, so I don’t end up scrolling.
I made a rule for myself that I would never go past page 2 of HN. So, each morning, I see 60 items, and if none of them interest me, then I just move on with my day. I think that's why I never became addicted.