If Universal had decided Hagrid's needed to be entirely enclosed the price tag would have approached Guardians level. And maybe some of that extra money for Guardians went to ensuring reliable operations. Hagrid's still does not operate at its intended capacity and likely never will.
In even keeled-ness, many rides don't. Guardians, even with a building a bigger price tag is falling flat on that for a while. Good thing Universal built two intimin coasters within five years vs a new major ride in a park every ten for DIsney.
And I don't know about enclosed coaster factor driving the price up that much. Don't forget how low in cost Forbidden Journey and Gringotts were created in comparison. Disney is just inflated.