“Of course there would. We get a hint of it here.”
Completely false. No one disputes there would be schisms, but so many official ones and so many as is? No, that is because of the very roots of Protestantism itself.
What's so surprising about that? Some are simply differences that are not related to salvation. Some are differences that do relate to salvation. No one ever said error will not creep into different "churches". We already see that happening in John's time when he wrote Revelation.