There are still many ways to complete a college education. At best, college can teach you about rigour and timely topics that are both worthwhile and necessary for independent study. Some shortcuts to these could be, e.g., to work as an undergraduate research assistant.
Another option is VC type of funding. If you already have the chops to be convincing and work on relevant topic, places like Thiel Fellowship or YC might give you alternative approaches to learning.
As for Gates I do not know. In general, I would assume that the value of a university degree has only declined since then.