At the noted temp in the first posting, no reason I can see to leave the gear down. MAYBE THEY FORGOT TO RAISE IT!!! Would not be the first time or the last.
What is extraordinary about this is the amazing verdict above, not the leaving the gear down after take-off! Please would non-747 pilots refrain themselves from reaching such idiotic verdicts and causes! Having flown 747s of 3 models for 18 years, I know it is a not uncommon event depending on brake temperatures which can quickly be critical, especially earlier Classic models. But don't make a darn fool of yourself pointing a finger of blame like this!