Just concentrate on your own team and don't worry about what others are doing.

I've come across others that do the same, deliberately not promote - but that's up to them. Maybe they want to try and even the playing field a bit as they can't afford to buy or are unable to farm for lots of tokens like other users?

Its each to their own. I've never not promoted (or been out of the top 4) simply because I could farm loads of Tokens. If I was in a position where I didn't have loads of tokens and I didn't want to (and I wouldn't) pay for them, then the option to tank a season to get rid of strong players and give me more chance to be competitive would probably be a decent option.