The biggest reason is my local public transportation. I live near a large city in northern West Virginia. The only bus that comes close to my address runs twice a day. Once at 7am and then again at 5pm. On top of that it would be a 20 minute walk, 10 minute bike ride, or 5 minute car ride to the bus stop. If I had to I could make it work but I can’t get groceries after work because I would miss the last bus by the time I got off work and finished my shopping. This means I would have to go out on Saturday at 7am and do my shopping and then catch the bus back at 5. Add on top of that having two kids and it’s just impossible. Unfortunately a lot of the US is like this. I wouldn’t mind if I had to pay more and my local government put more effort into public transit but that seems to be low on their list of priorities.
I will say that electric bikes and self driving cars in the future may change everything for the better.
It should be that the more popular the post is the more interaction it needs to stay at the top. That might even out the newer smaller posts.