Easy to say flippantly, but my colleagues (let alone my network) are distributed across 10+ countries on four continents. My local 'meatspace' has nothing to offer me career-wise. A professional network needs to be online.
But it doesn't need to be through a third-party website. It's entirely possible to cultivate and maintain such a professional network by directly communicating with people. That's what I do, and it causes no trouble.
Meatspace isn’t going to work that well going forward because of wfh making physical proximity irrelevant. I’m contemplating a move to a company located in NYC but I live in Dallas (it’s wfh obviously). I wouldn’t have been able to make that relationship in meatspace as I’d never even heard of the company before let alone shook the hands of someone who worked there.