He was proved right with what happen to Shrimpy. Shrimpy didn't change/modernize and they're losing the estate. Robert modernized, albeit under protest, and they've become self-sufficient.
But I still like the idea of Daisy becoming independent. And I like her relationship with her "dad."
We also know he was proven right by history. From what I've heard, it took a while for the producers of the show to find a suitable location for Downton Abbey since most of those big houses were demolished after the war and split into smaller estates. The house they use on the show is one of the few left standing.
BTW, have we ever learned anything about Daisy's family? What kind of background is she from?