The actual powerful network effects are essentially a somewhat benign form of cronyism, not mere inspiration from other entrepreneurs. People do more business with less haggling with friends than with strangers.
This is how humans work. This cannot change with UBI.
But there are also ideas. Even in fields where there's basically no money, half the world's innovation happening within a circle of a few miles is routine. For instance this happens in music, repeatedly.
Sure, on some level he could have done the same work in his garage, in some quiet seaside town full of retired people. But he didn't.
Reducing the friction in long-range interactions obviously has its upsides. But these hairless primates still pick up lots of stuff from being around each other.