ATC would not know about the gear, and while ATC in DXB is pretty good, I very much doubt they're checking gear through binoculars (where does?) as they're just too busy with the traffic flow.
However, for the pilots to omit the gear selection, forget the checklist (EICAS), miss the GPWS gear warning and not notice that the aircraft was exceptionally slippery on late finals seems somewhat unlikely. Let's stop the ridiculous assumptions and accusations, shall we?