KanecoSome people are just oblivious on competitive tf2 and when they do know about it, the entry barrier is simply too big, because the game is a lot different than what they are used to play or because it requires you to put a lot of effort into finding a team, etc...
When I came into competitive I already knew about competitive, I have watched a few streams here and there and played a few lobbies but never took part in any real competition or season.
I was a regular at a pub in my country and one day the community there decided to create a portuguese tf2 league, and what they did was go around on the most frequented pubs and announce it and say they were also creating and accepting solo signups so that you could be put in a team by the admins with other beginners, I went with it, the league was a fail, it didn't even finish, but it was my first tf2 team and real competitive experience on tf2 and from then on I never stopped playing.
I reckon this is one of the most important things, making sure there are constant opportunities for newbies to join our scene, putting them out there so they know they can do it and try to help them climb this entry barrier, whatever way it is.
a really nice way was the newbie mix. That's how I got into comp and I was a trader as well. The newbie mix allowed me to meet people around my skill level and learn the game at the same time. I was also able to make a team with the people I knew and recognized some others have done the same since. I know it's asking alot but maybe a revival of newbie mixes is necessary?