Based on a reading of A.N. Wilson's biography of Hilaire Belloc, Father Alexander Lucie-Smith asks that question in a Catholic Herald article:
. . . I once lived with a priest who loved to preach on the subject of “Europe is the faith, and the faith is Europe”; and yet Belloc himself is nowadays neglected.
Mr Wilson’s excellent biography tells us why in terms that are rapidly understandable. Belloc was cursed with the necessity of making money all his life, and consequently wrote far too many books, most of which were hurried productions, indeed not written at all, but dictated. In this he sounds like that other most prolific author, Dame Barbara Cartland. Belloc could turn out a book in a week. He was a constant traveller too, and how he got any time to do any reading remains unclear. His history books are very thin on fact and solid research, and long on argument, and the arguments, one gets the impression, are repeated again and again.
Father Lucie-Smith also does not admire Belloc's Path to Rome, which I have mentioned before, and did admire. I do think the headline unfortunate--its one thing to say that his works might not stand the test of time, but to assign the man to oblivion is a little harsh. I do believe that Frederick Wilhelmson and Joseph Pearce, and Father McCloskey would disagree--and the owner of the Hilaire Belloc blog would definitely disagree!
I have enjoyed reading Belloc's Path to Rome twice, and know that much of his work on English and French history, while not up to the standard of profession history, has been proved correct in his interpretation of events. I believe it was Father Vidmar in his book on English Catholic historians writing about the English Reformation who said that Father Hughes and the later revisionists provided the footnotes and rigorous research Belloc neglected. Frederick Wilhelmson concurs:
Time prohibits my detailing Belloc’s revolution in English historical writing. Suffice it to say — and this is said formally and altogether without rhetorical emphasis — that one man, Hilaire Belloc, turned the whole writing of British history around. Since Belloc, nobody can get away with understanding the Reformation as the work of high‑minded souls bent on liberty and democracy, noble souls who brought England out of the darkness of Catholic superstition and medieval obscurantism. Others footnoted Belloc and traded on his vision. They did well in doing so, but the vision was his — as was the persecution of silence that followed on his work.
We have benefitted so much from Belloc's "revolution in English historical writing" that we perhaps take it for granted now.
I disagree with Father Lucie-Smith: Belloc is not best forgotten!