Not that I am the celebrity spokes model for flat bars, but general comments:
1) Using flat bars is not a lack of physical conditioning that needs to be trained away.
2) Raising the drop bar portion to the height of flats is silly, as it would put the hoods and tops 4" higher than your flats, so you could sit bolt upright going down the road. You would then have one meaningful riding position (the drops) which destroys the whole non-sensical "drops give more hand positions" bunk.
3) On drop bars, your palm is perpendicular to the road surface 90+% of the time (on the hoods, in the drops, in the top curve), and only become parallel to the road in one position (on the tops). Why do I mention this? Because my wrists get tired, and I can vary my hand position, wrist position, load bearing contact point, and elbow bend far easier on flats. On drop bars, the tops is the least used position, is uncomfortable if you have large hands, and stinks for climbing, because you close off your shoulders.
4) Flat bars on the road are usually fairly narrow (mine are 550 mm wide), and are not always riser bars. You can get a lot of variety in flat bar to tailor comfort. Mine are straight bars, with a 3 degree bend that I have pointed mostly down. Which again means I can tailor a fit exactly to my desires. They didn't come stock this length, I incrementally hacked til I had what I wanted.
5) I own a bike with drops, and use it at times. Short fast rides. All day rides are the flat bar bike.

Most importantly, on group rides, flat bars anger every rider you pass. That is almost reason enough.