421dog
"My understanding from a few 747 jocks of my intimate acquaintance, is that the received knowledge was to never transition to a slip upon landing,"
Yep, the aircraft geometry was such that if you allowed any significant deviation from wings level to develop in the flare you were in danger of smacking a pod. There were some graphs around, certainly in manuals for the 100-200, that illustrated pod ground clearance vs. pitch and roll that were quite quite eye watering...it could be tight even wings level.
"rather, let the undercarriage sort it out."
It would...and there was certainly an argument that on wet runways it was better to get the aircraft with all it's associated momentum attached to the concrete whilst the fight path vector was still aligned with the centre line, rather than spending too much time finessing the yaw alignment.
As a final point I know a lot of the comments about landings seen on streaming sites are wide of the mark but before being too critical it's always worth bearing in mind a lot of the performers seen on TV maintain recency with maybe two or three landings a month at best, might be at the end of a v long duty day and it might be oh dark horrible on their body clock.....