Do you have frequent social interactions with other professionals? Off the top of my head (and from personal experience) some ways to meet people:
- Network within your company, particularly with people in other disciplines
- Alumni events for your college
- Send your kids to private school and make friends with parents (or have gone to private school yourself)
- Play sports that professionals play like golf, tennis, pickleball?
- Attend networking events (though I haven't really tried doing this since covid)
- Get an (in-person) MBA
- Marry/date someone with a wide network
Generally I think it’s all about the buildup after a certain amount of time of working in your industry. And not only 9-5 working but just doing interesting projects and attracting such likeminded people.
Famously, the GitHub co-founders and the Instagram co-founders met at co-working spaces / hacker meetups. Tom Preston-Werner gave an interesting talk on how to build successful co-founding teams and products: https://www.youtube.com/watch?v=mGTpU5XUAA8