Why are the dancers' pivots so flat-footed compared to those performed by baller

Question:

Why are the dancers' pivots so flat-footed compared to those performed by ballerinas & rhythmic gymnasts?

I watched some of these dance competition programmed "So you think you can dance" and "Dance fever" and those dancers' perform the pirouettes/pivots are pretty flat-footed compared to the ones performed by ballerinas and rhythmic gymnasts, who have almost a perfect straight arch on the pivoting foot. Do the dancers intentionally pivot with a partial flat foot in order to get more revolutions in or they just don't have the strength required to maintain a ballerina quality arch on their heels?

Best Answer - Chosen by Asker: Pivots are executed differently in different styles of dance. Ballroom pivots are intentionally flat-footed (compared to ballet pivots). Ballroom is danced in a couple. Besides just saying it's a different style of dance and you want a certain look to it, I think it is pretty hard to match for two people to go on high arch together in perfect connection still matching the height perfectly. Also, they have to manage their relative position. I'm trying to imagine how'd pivots feel like if we danced them on high arch, I think it wouldn't work in a couple.
I think you are right that we don't have the same strenght in the feet and in core muscles as ballerinas do. Ballroom was intended for regular people, only later it became more strict and developed competitive division. It takes a lot more balance to perfom ballet pivot than it takes for ballroom pivots. i tried both. Flat-footed pivots are a piece of cake compared to ballet pivots/pirouettes.