This is 100% true in my experience. Human connections are one of the most important things not only in business, but in life.
You can make connections everywhere starting with your family. Building strong connections with your parents, siblings, and relatives is very important for emotional support which you're going to need throughout your career. High school friends may or may not impact your business life, but those friendships tend to stick around forever and the more of those you have the happier you are going to be and the more energy you are going to have to succeed in business. College tends to be a better place to make friends that are also likely to walk with you along the same career path. In my experience, college friends have been the most important connections that helped my progress in my career. And last but not least, once you graduate from college and start working, you will have the chance to meet lots of great people. Make sure to invest enough time to cultivate those relationships too.