Sounds like somethings not right here.
Cleared for take off then not, this is FRA not some third world, new world we have LVPS and we are going to be the next super power etc Delhi Belly etc.
I hate to say it but compared to lots of airports Frankfurts generally one of the good ones.
LVPs in force distance between aircraft is increased to 8nm, parallel ops in FRA I assume, they have lots of runways there, so why have departures and arrivals on the same runway.
More like as mentioned engine run up forgotten in fog or a config warning, speed brake not in the detent etc
Who am I to comment as I sit here in the comfort of my lounge.