The old philosophers had much greater breadth because the whole vista was open to them. They were treading on soil for the first time. Newer philosophers are dry academics who are just filling in a few details. Who wants to read that?
Philosophy is an unbroken conversation going back thousands of years, why would we want the cliffnotes summary written by 'academics' who most times demonstrate a fundamental lack of understanding of what they're writing about when we can go straight to the source and read the original.