Honestly, that happens in virtually every world. The top owner trades the 31-32 y/o for a 23 y/o. The older player is really good but expensive and declining. If you think you're missing 1-2 pieces, it's hard to decline the offer. Problem is the top owner already has his replacement because he traded a couple of 31-32 y/o guys the season before for that replacement. It's a cycle and, if you don't understand that, it's repeatable.
And, if the owner is in the other league, there is absolutely no reason to not make the trade. Most of us don't care who we face in the WS, we just want to get there first. It's up to the other 15 guys in that league to prevent him from getting there.