You are defining "beat" as 1v1 in lane.
I am defining "beat" as defeating his team and killing their nexus.
By your definition, yes... very few champs can "beat" Pantheon. He is one of the strongest laners and duelists in the game early on.
But you CAN beat his team... which is what I am TRYING to say to you. If you stop seeing the game as a 1v1 that happens to have other people doing stuff elsewhere on the map and you start thinking about how you can defeat his team and claim victory, then you will understand.
But you don't. You just see that he can 1v1 you and cry because you want to 1v1 people and he's better at it than you. Stop that. Or just fucking pick Pantheon if he's THAT broken. Or ban his ass... everyone gets a ban now.
What you call broken I call pretty good design. He has clear strengths and weaknesses and isn't an overloaded monster like most of the new champs we get are. His kit is outdated and very point-and-click true... and fighting against him is a little boring... but y'know... so is fighting a LOT of other champions. Sometimes you're just not gonna be able to go ham and get fed. Sometimes you need to win a game by being smart enough to play passive or defensively. If Pantheon didn't fall off, I'd agree that he was broken as HELL. But he does. HARD. Stop slamming your head against a brick wall and just play around his obvious as hell weak mid and late game.
There will ALWAYS be someone who is just kinda the best 1v1 duelist for any given role. I'd rather have it be someone like Panth who does very little else to pay for that power than some overloaded monster of a champ who can spank you 1v1, splitpush, teamfight, assassinate carries and burn down tanks too. He does ONE VERY predictable thing. If you can't get around that... well, nothing anyone can say will help you.