I would have to disagree with the concept that those who are very successful put it all on the line and risked losing everything. Most of those I know who are very successful in business are where they are because they had a plan, and worked their tails off for a long time to attain it. Granted, with any business venture there is a risk that you will not be successful and may lose some money. However, in this business, it doesn't, or shouldn't, take a 2nd mortgage or a large loan to get going.
There is a lot to be said for caution, planning, and assuring you have a safety net in place. In my case, as well as with others, that safety net is a full time day job. Sure, I could go quit, borrow a pile of money and jump in with both feet, and I may see success a bit more quickly. On the other side of that, however, is what am I going to do if I find I just can't make this work? Sure, when you get to the island and burn your ship, you're forced to survive. But what do you do if you discover there is absolutely no way to survive on this particular island? You better start building another boat. Some of us prefer to keep our boats anchored just offshore until we are certain there is going to be sufficient food and water and shelter on the island to survive, and until we are certain we even like the damn island.
Sure, part time work=part time income...but that part time income is ALL gravy at this point, and can be set aside for equipment, marketing, or for a lot of gasoline and matches when I finally do decide to burn the ship. I can work at building this, and learning all I can, without the added stress and concern about whether I can make my house payment or buy groceries this week.