Lieven, I suppose that Margaret of Anjou tought that they were good enough to fight for her son Henry VI, but not good enough to start a royal´s dinasty
At the end, Margaret was the proud daughter of a duke of Anjou that was also king of Naples, and a duchess of Lorraine in her own right. I don´t believe Margaret could understand how the widow of Henry V, a princess Valois, had children by a secret marriage with a welsh man as Owen Tudor.
But this is my point of view...