Businesses are the foundation upon which all wealth is created. If you do not own a business, you are extremely unlikely to ever enter into the top echelon of personal wealth figures in this world. While there are a few elite people out there who have gone on to do some amazing things despite being employees or self employed people, for the most part getting rich involves starting businesses. Notice that we are talking about businesses, and not just about a business. While having one is definitely a good start, having more than one is a great way to have a hedge against any one of them failing.
When you start businesses, you would do very well to concentrate on one to start with. Generally, especially for early entrepreneurs, it is extremely difficult to get a business off the ground. And when you try to focus on two things, the best you can ever do is go cross eyed. Generally what happens when you try to focus on getting two businesses up and running at the same time is that neither one succeeds, and you end up having invested a lot of time, energy and money into things which will no longer exist. Nobody wants to do that, so focus on one at a time.
Of course, once a business is off the ground, you become less like Hercules trying to hurl a boulder, and more like an airplane pilot who has a lot of sophisticated tools at your disposal for keeping it in the air. It is a whole lot easier to keep several businesses running smoothly than it is to start one from zero and get it to the speed where it can maintain a high, steady altitude. As time goes on, it will get easier, even if you have a hundred businesses. It’s the hardest early on.