To the 737Ng Guru's here..
Is it possible that being hot and hi they selected 0 or airport elevation on the mcp?
Hence leading to an idle descent in FLC, with no approach mode selected? The resulting higher alt could have kept the engines at idle.
Sorry, I fly a bus to my Boeing terms and logic is minimal at best.
Perhaps the RA's played a factor. But by the looks of it, this is not really an issue in vmc. After all, unlike the bus, the thrust levers move don't they?
Again, sorry for the speculation. Just looking for insight.