While reading that introductory word balloon, keep in mind - this is the very first issue.
Notice that to inaugurate this feature, they chose what they thought were the most important figures to introduce - the guys writing & drawing the Fantastic Four - emphasized by using the FF to introduce the feature. They are, after all, the First Family of Marvel Comics. Their adventures form the very core of that universe, both on and off planet Earth.
They are obviously the most important part of the Marvel Comics Universe.
Sure wish the decision makers at Marvel Comics could get their diapers changed and remember that.
(Yeah, yeah. I know. Imitating Snell again. But when the man's right, he's right!)
Page 3 boys from FOOM #1 (1973)