Yup. There's a lot of factors at play. We're a very ahistorical field; lots of folks are self-taught and therefore reinventing everything is normal to them; the dev universe is heavily siloed into "Web+UNIX" versus "Microsoft" versus some now moribund siloes (Websphere! Solaris! Alpha!); Microsoft have almost no community compared to the FLOSS world (although .net is changing this a bit); and finally the simple fact that COM and you and I are very, very old.

I'm not even sure that reinventing COM would be a bad idea - you can definitely do some great things with it, and the specific implementation details of COM are crufty. But doing so deliberately rather than accidentally would be better, with a review of benefits and problems of COM approaches.