The Great Schism of 1054 can be viewed as just a corporate split due to political pressure, which it was. It didn't seriously change anything about the business of the parent company.
It sort of did, though. Easier to define your own standards when you don't need consensus from peers, no?
In either case, I think it's funny to consider the Roman Catholic Church as "the parent company". It's a little dismissive of all other Apostolic Sees and sort of rewrites history a bit to imply that Roman Catholicism was the root of Christianity. Technically, you'd want to use the pre-ecumenical council of Jerusalem (year 50) and that nearly all modern Orthodox churches and the Catholic church share a starting date.
That's the only reason the Roman diocese became dominant. Not any sort of lineage or pedigree.
There's a very informative youtube video about the schism: https://www.youtube.com/watch?v=a6rWf0k8d78