If the Ethereum developers don't reach the majority of people when they plan to do a hardfork, there is a big chance, that the network will fork.

But even if the chain forks, this does not mean, that the old chain can survive.
If you don't have a developer team which continues to work on the old version or people who are willing to keep the old chain alive, this old chain will become obsolete after some time.

The biggest problem with a fork is, if you have 2 or more parties who disagree with the changes. Even when everyone is OK with the new version, you might get a fork because some people are not aware of the new version. But after some time they will identify them self on a more or less dead chain and will switch.

I think a real fork, where both sides survive is more a political problem than a technical one. Bitcoin is the best example for this.