How Beatty was fired and Carradine was hired

From the few things i’ve seen, Carradine doesn’t look like more than a one dimensional actor. But apparently he’s done some fine acting jobs in many films that I haven’t even heard of. So I can’t really judge his acting ability until I see some of those films that you guys mentioned. But the one thing that I can’t get over is how he got the lead role in Kung Fu when Bruce Lee was originally going to star. >:(