For those unfamiliar with Church history, this gives the impression that the Church was chugging along just fine until 1054, when (at that exact date) everything started to fall apart.
Wait, you mean Christianity has always been a fragmented mess?

No. I think
Asteriktos is trying to point out that the schism between East and West is something that developed over several centuries prior to 1054 and didn't really become the complete mess we know today until several centuries after 1054. The schism isn't a singularly catastrophic event that happened at a specific moment in time.