I think it all depends on your definition of fusion. Just like the definition of progressive rock, it's different for different people.
However, one generally accepted definition is "jazz with some rock elements." Not far removed from that would be "rock with some jazz elements."
Many of the "rock" bands here on the Moon incorporate jazz elements. There are tons of examples, it would be pointless to list them all.
So it's my humble opinion that fusion certainly belongs here because "jazz-rock" and "rock-jazz" are awfully close. Kinda like "blue-green" and "green-blue" in my box of crayons.