If your whole department or project is being let go loyalty and personal relationships doesn't matter. If your department or project is one of the ones told to manage out poor performers more aggressively or to cut X% of headcount being someone your manager can count on is going to make you substantially less likely to be one of the people managed out or cut.

Sure, they might bring in consultants like it's Office Space but those consultants ask everyone what they think of their team members and keep score and in that scenario it's still better to be the person everyone likes and/or respects with more than the absolute bare minimum work output.