Business is about adaptation, not preparation.
Business is about both preparation and adaptation, and I'll tell you why. You made a good point about how an individual can face challenges while running a business, and they should be able to deal with them and that's only possible with experience, but let me tell you that for one to start a business, and make it reach the position where others may try to destroy it, they need preparation for that to happen because you can't just get up one morning, and say that you are going to start a business and it happens magically. Starting a business is a long process, and the first step of that process is to make a proper plan, which comes in the preparation category.
Once a business is established, up and running, that's where adaptation comes in, because once your business starts gaining traction, you will start facing some challenges, such as having competition with other similar businesses, people trying to spread negativity about your business or brand. So, during that period, you should be able to adapt and make changes, changes that will make your business stronger so that it doesn't get affected by those things.