One more reason is that it's the start of new session and due to changes and rewards most of the players are playing. That's why it's hard and harder after gold
Every kog was once a rookie. PVP was restarted a few days ago. Of course you will be dueling with competitive players from the start. Wait 28 days, and you can play rookie duelists if that is what you want.
I agree it has, I played this game back last summer and made it to platinum without even trying. Now I can barely make it to Gold without an amazing deck. Killer magic and trap cards have become so readily available amongst other things I guess. Not to mention cyber angels and other decks that wipe out your magic/trap zone.