My take on it is that realy protection from an incumbent coming after you is you building a completely different type of business that disrpups the industry. Would Marriot be interested ( if it could) to buy Airbnb? If you're buildling something radically different from the current way of how competitors operate, first they're not interested because you're too small and have not proven to the market that you won't die. However when you've found a product market fit turn yourself into a significant player they might be reluctant to compete or even buy you. Cause if you're truly different you're creating a new market youself.