Em, I disagree. I think there are actresses who can disappear behind their characters: Christine Ebersole and Mary Louise Wilson did it in GREY GARDENS, Donna Murphy did it in FOLLIES/LOVEMUSIK, and Audra McDonald did it in 110 IN THE SHADE. At no point during their performances did I feel I was seeing Ebersole playing Little Edie, or Murphy playing Lenya, or McDonald playing Lizzie.
There a number of actors that are brilliant performers but they always play their characters as played by them. Mandy Patinkin does this, Harvey Fierstein does this, Elaine Stritch does this, Kristin Chenoweth does this, and Patti LuPone most certainly does it. It doesn't mean they are any less fantastic than the other actresses I mentioned before, but one can't deny that there are actors who disappear behind their roles and performers who play themselves as playing a specific character.
That's what Brantley criticized in his review of GYPSY when he mentions that sometimes LuPone creates a distance between character and performer. I haven't seen GYPSY and from what I hear what makes her performance so great is that for once she isn't playing a version of herself, but I wouldn't be surprised if she were tempted to do this at times.
"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"