Immobile carries are such a dead trait in League of Legends. Back in the older seasons, being immobile was okay, there was a fair balance of immobility and mobility, and champions were rewarded for it. Nowadays, every tank has the damage to kill a squishy target, and every other champion has mobility, making immobile champions useless.
You can't pick an Orianna or a Ryze, or an Annie, because they're immobile. The jungle role is becoming more and more prominent, which I already dislike as a solo laner because it often results in players that can't outplay their opponent in getting help. I'd have no complaints but in soloq you often have to carry your lanes and if you're getting camped ik my lanes wont win on their own (this isn't my complaint). Point is, junglers aren't punished for visiting your lane over and over, they're too relevant, meaning that my only way of survival is picking a mobile champion that can escape ganks. Sitting at tower on an immobile carry doesn't make you safe. If anything, the false sense of security would get you killed more.
Orianna was my most played champion across 3 seasons and this season I have played her like once or twice. There's no place for them in league currently, and the hextech belt is a bad way of trying to implement mobility, because only the healthier building champions would ever want one.
When the game starts restricting champion usage because of a different role, that's when for me, it stops becoming fun. I can't play the champions I used to love because junglers are now on par with laners in terms of levelling and strength. Supports haven't received this type of balancing, and probably never will, I don't see the fun in junglers being this powerful. Barely have to hit a spell to make a trade swing 1 way even under a tower.
Aaaand, this is why I can stomach 1 game of league if my friends force me onto it before going back onto overwatch where the game feels like you have an impact on your own. A team game that actually uses an element of skill to enable you to carry.