Uber is ostensibly valued at over $60 billion. To really be ‘worth’ that they have to grow rapidly, and arguably beyond on demand ridership into a ‘transportation logistics company’ moving goods and not just people. And they have to actually make money.
While there are certainly network effects — the more consumers use Uber, and the more drivers offering rides on their platform, the more valuable they are. The first person with a fax machine had a useless piece of equipment. There was no one to send them anything, and they couldn’t send a document to anyone else. The fax machine became more valuable the more people that had them. But even there, when’s the last time you sent a fax? I believe I’ve sent two in the past year.