Fun to speculate, but not much of a chance in reality. She has committed to the steeple professionally. This deep into her pro career it could be a career-ender to switch events and fail. No doubt she has a contract kicker if she makes national teams (much more likely than medalling in either event), and with 2 World Championships and 1 Olympics coming up she has much more of a chance in the steeple than 1500. Also, starting over doesn't just mean physically. 4:05 is good for a steepler but probably wouldn't get her into Diamond League meets unless she was also the American champion. She would literally have to start from the bottom again running second-tier meets. By the time she worked her way up to Diamond League, if that ever happened, she would probably be past 30.