To me, passion in the context of starting and building a business is about a deep commitment to serve the a source of pain or create a source of delight for a market that you feel a strong connection to.

If what's driving you is an attachment to a particular solution, then if the solution doesn't work, your commitment to the entire endeavor evaporates.

But, if your attachment is to a market, you stay motivated and have a much easier time pivoting as needed and surviving until you find the model and solution that work.