luck plays an important part, but not everyone realizes it or admits it.
It is far too simple to say that it is only luck. Persistence and good processes often lead to “luck”.
"Luck doesn't come to you, you go to it".
Which is to say you are right: if you keep showing up at stuff you will eventually get lucky. Luck can only happen to those who try and get lucky. Our real world resembles an MMORPG game -- you need a team for 98% of everything -- then I'd say both you and your parent poster are correct.
If you are successful several times against the odds it's probably not just mere coincidence anymore. You know, stats.
You also likely have funds to float you for longer.
You also likely have a network to leverage/exploit.
These external things all can stem from a lucky first go.
Then following your advise in less lucky situation is likely to fail.
Though, realistically, the chance should increase for the following attempts, because you can reuse some resources and contacts you gained with the first success. The first startup is like "I need to succeed within three years, or return to a regular job to pay my bills". But if it succeeds, the second startup is like "I can keep trying as long as I want to, no pressure".
This is soluble.