That is not how it works! That's not how anything works!
NBA is not a good example because it is a franchised league like most professional sports leagues in the US.
There are basicly two models for sports/esports. Franchised league vs open circuit/tiered leagues.
Since you're from the UK let's take for example the FA cup in football. A complete amateur team can win it all, of course it is very unlikely. But they are not denied the opportunity to do it. If they are the best they will win it.
And about your passion. Is your passion to clear the raid or is it to be the very best like no one ever was? If it is the latter you do what you can to be in the most favourable position, be it extra time to do it, surround yourself with better teamates, make it your job (either by streaming or being paid by an organization to do it). The latter also works for pretty much any sport.