No offense to gymnasts, but FS programs are a complete experience in themselves in a way no single gymnastic routine can ever be. When skaters take to the ice for their SP and to a much greater extent, the FP, there is the sense of the whole ice rink being a stage for a complete experience of moment.
Part of that experience is the program being skated for the first time on an large Olympic stage of ice. When I think of some of my favourite Olympic FS programs, such as Yags 2002 or V/M 2010 FP to name just a few, there is the element of surprise. That is, the skater's bring heart and soul as well as body to the program in creating an unforgettable moment. There is 4 1/2 minutes of moments that tell a story. Gymnastics just isn't the same IMO.
To have those programs skated earlier in the Olympics in a team competition would water down the impact of the individual FP, IMO. Skaters can't bring heart, body, and soul to the same program in the same way two times. And if they just go through the motions in the team competition, the FP won't have the same wow effect. The skaters have to create a moment twice that can only really be created once to full effect.