Riding bicycles alone isn't going to help; its going to take decades of urban planning to fix the last 60 years of mistakes.

Maybe look at it as joining a community, not specifically being about cycling. Being a cyclist gives you something in common with someone else that you can talk about it and, when doing it, it's rather visible. A running club, writing group, etc. can be similar.

I'm a transportation cyclist, but I don't think being a cyclist has measurably increased the number of friends I have. It did give me something in common with quite a few of my friends, but I didn't meet any of them through cycling. For a while I tried joining a cycling club, but I found that I didn't have much in common with racing cyclists.

Being a cyclist did however does apparently increase the number of people who seem willing to harm me, unfortunately. That's not loneliness, but it's not good either.