Worldwide Church of God rejected truth

21 hrs
Question

Back in the late 1990s, the Worldwide Church of God, headed by the late Herbert W. Armstrong, used to teach the truths about the 7th day Sabbath, Holy Days, dietary laws, etc. But then abandoned all of that and adopted Sunday worship, Christmas and Easter, abandoned the dietary laws, etc. They changed their name to Grace Communion International. Any thoughts on why this happened?