I still remember the first time I saw Castle Wolfenstein 3D. I was a junior at Stanford, and for the first and only time in my life (thank goodness!) I was living on an all-male environment (my dorm that year had a male floor, a female floor, and a co-ed floor--I'm not sure why my roommate and I ended up on the male floor).
Down the hallway, Haresh Kamath (now a leading light in the alternate energy field) had a 386 PC, complete with Wolfenstein 3D and other classic games like Star Command. The members of that hallway spend endless hours sitting around Haresh's computer and playing those games. Even then, it was clear that id had created something special.
Of course, at the time, I assumed this amazing game was the product of some huge studio. Nope.
"Carmack disdained talk of highfalutin things like legacies but when pressed would allow at least one thought on his own. “In the information age, the barriers just aren’t there,” he said. “The barriers are self-imposed. If you want to set off and go develop some grand new thing, you don’t need millions of dollars of capitalization. You need enough pizza and Diet Coke to stick in your refrigerator, a cheap PC to work on, and the dedication to go through with it. We slept on floors. We waded across rivers."John Carmack is oversimplifying a bit; not everyone has the advantage of being one of the most brilliant hackers of all time. But he's essentially right. Time is money; if you have the ability to invest the time, you don't need the money.
And Carmack was doing this in the early 1990s, when he had to distribute his software using bulletin board systems. We were still years away from Netscape.
If you have an idea, and you have the time, you can make it real.