In the new reality Jamie had wished up, she'd never had to drop out of school. As sad as it sometimes was, her life at that point was not something others admired.
Her new life was much improved, although even she didn't know to what extent. But, with her life doing so well, she wasn't really in need of a wishing stone. The stone therefore, had gone to someone who would make some wishes on it, as per Jon's earlier wish.