One aspect of the Russia Hoax that may appear puzzling at first glance is the amount of effort the FBI put into framing George Papadopoulos--overseas travel, cooperation with foreign intel services, possibly borrowing assets for use in the entrapment schemes that were designed to ensnare Papadopoulos in the Russia Hoax narrative. By comparison, Carter Page seems to have fallen right into their laps--which is exactly the case.
I think this will make more sense if viewed from the perspective of what the FBI was attempting to accomplish within their administrative framework--into which everything had to fit.
It appears that a decision was made early on that trying to label a single person--or even two more or less unconnected persons--associated with the Trump campaign as a Russian spy would not be sufficient. If that had been tried, the failure to warn and brief Trump would have been utterly implausible. What was needed was to present a plausible case that the supposed Russian connection to the Trump campaign was systemic. For that what was needed was a network of individuals that was active in a key part of the campaign--the foreign policy shop. If such a de facto network of Russian agents working within the Trump campaign could be plausibly claimed, then the FBI could do what it actually did do with Crossfire Hurricane--open an "enterprise counterintelligence investigation," with the de facto network being the targeted "enterprise."
As I explained in Mueller's Enterprise Witchhunt, an "enterprise investigation" is defined in the FBI's guidelines (DIOG) as follows:
Enterprise defined: An enterprise is a group of persons associated together for a common purpose of engaging in a course of conduct. The term “enterprise” includes any partnership, corporation, association, or other legal entity, and any union or group of individuals associated in fact, although not a legal entity.
Associated in fact defined : The term "associated in fact" means the persons have an ongoing organization, formal or informal, and that the persons function together as a continuing unit. (DIOG 8.2)
The problem for the FBI, then, was to establish such an "enterprise", an informal group of persons functioning as a unit in fact, although not a legal entity. Who would be the members?