They never had the intention of getting a dancer/singer in the role for this revival. Marisa Tomei did the first workshop, then I believe came Jenna Elfman (why were people so into the idea of putting her in a musical?), then Jane Krakowski, then Applegate. None of them were trained dancers in the way that a Gwen Verdon, Debbie Allen, Bebe Neuwirth, or Donna McKechnie are.
"Some people can thrive and bloom living life in a living room, that's perfect for some people of one hundred and five. But I at least gotta try, when I think of all the sights that I gotta see, all the places I gotta play, all the things that I gotta be at"