There are different definitions of time that lead to people arguing past each other.
There is the idea of time as being the sequence of events in the world/universe.
Then there is the idea of time as being the measure of that sequence of events, which is what 4x seems to be getting at. As far as measurement is concerned it is not needed (i.e. necessary) in the universe. Generally, people have a need to measure. The universe does not.
time is that thing that keeps all other things from happening at once
That would make time to be some sort of force. I don't think it is. Time doesn't keep all things from happening at once. Time is the fact that, because of other circumstances (namely, the physical properties of the universe), all things don't happen at once.