Back in October I went to a one-day event about the future of United Church theology. One speaker kept emphasizing the need to be relevant. She advocated jettisoning all sorts of things that have been pretty central to Christianity – including salvation, and the existence of Jesus himself – in favour of things that would be more “relevant” to people these days.
I think that speaker was confusing “relevance” with “popularity.”
I was also reading a biography of Dietrich Bonhoeffer. Was he popular? Certainly some in Nazi-era Germany were inspired and encouraged by his teachings about the centrality of Jesus (vs. all other things which we try to put at the centre). But many (probably most) folks who called themselves Christians thought he was out of touch with the society, with modern times, with the needs and values of his age. Even some of his allies thought he went too far.
Bonhoeffer has since become very popular, among all sorts of Christians. (Though I wonder if we really engaged with his thought, how popular he would be. I’ve heard it said that he is popular because of his biography, not his theology.)
Nonetheless, was Bonhoeffer popular in his time? No. Was he relevant? Extremely.