You have probably never gotten a straight answer because it's not an easy question to answer.
The webmaster is Pete Werner. He owns the site. The assistant webmasters were all asked by Pete personally, and are most or all people who have been with the site from the very beginning. They are people who Pete got to know personally and whom he trusts implicitly. To get to be a webmaster here, in my opinion, you would have to have been a moderator here for many years.
You become a moderator by being asked by Pete or one of the assistant webmasters. There is no set criteria and it's not just something you volunteer for. The webmasters watch the boards for people they feel would do a good job and fit in. If I were a webmaster and had a say in who was picked to be a chat host or moderator (which I don't, thankfully) I would look for people who had been here a long time, who were helpful and courteous, and who stayed away from controversy.
You are always welcome to express your interest in becoming a moderator or chat host to one of the assistant webmasters.
That's about all of the advice I have to offer. I hope that answered your questions.