Honestly though, it's not a secret on how to become a VA. It just takes the same (if not more) work as becoming an actor or writer and both of those really boil down to perseverance, marketability and luck. The tools are all out there, and easy to learn on the internet, it's just not something people think about Googling.
Most VA's seem to start out on the Acting track, or working in a less visible position at the recording studios. I've heard of some VA's coming from Radio and local news, but in the end, you have to start with some sort of agent or managing group that can professionally record your demos or help you get marketed to the places you want to be employed at. People like Todd Haberkorn have agencies that plan their convention tours, acting jobs and voice acting jobs. Other people eventually decide to do it themselves or higher a PA to do it in house. But the easiest way to get into any entertainment firm is to start at ground level (getting coffee and pushing papers) and see what the producers are looking for and hone those skills. You can take the route of hiring a vocal coach and getting a agent and that can fast track you to jobs if you've got the talent they need, but you have to be willing to really get out there and make yourself known, by taking any jobs that come your way and get your voice noticed. Voice acting is an up and down sort of thing that one can start doing, and spend years and years getting little to no income from, but through perseverance small jobs can snowball into bigger ones and you could eventually land a role that makes you a name in the industry worthy of calling up for potential castings. It's all about how dedicated you are to the career, just like anything else. But you need recordings of your voice (like a portfolio of your vocal capabilities) and you need a plan and a direction. Pick a company and start looking for minor openings, that's the easiest way to get your name and face recognized.
Each person seems to get into VA work differently though, and it changes with EVERY generation, so the problem would still remain that YMMV in that, what worked for Vic or Sonny, may not work for the next generation of voices.