Note that I'm not claiming that some competent people could fix HURD right now if the political environment were better. It's more that the politics moved the project into the least tenable position. I don't know if there's a complete history somewhere, but just some things I managed to piece together from Wikipedia articles:

Berkeley wouldn't cooperate with development on the 4.4BSD-Lite modified kernel, so in 1987 HURD decided to go with the Mach microkernel. But then they waited 3 years for licensing issues to clear up before investing any real effort into it. CMU stopped work on Mach in 1994, so HURD switched to Utah Mach. Utah stopped working on it in 1996. GNU kept working on that one under the name GNU Mach. And then (from Wikipedia): "In 2002, Roland McGrath branched the OSKit-Mach branch from GNU Mach 1.2, intending to replace all the device drivers and some of the hardware support with code from OSKit. After the release of GNU Mach 1.3, this branch was intended to become the GNU Mach 2.0 main line; however, as of 2006, OSKit-Mach is not being developed.

As of 2007, development continues on the GNU Mach 1.x branch, and is working towards a 1.4 release."

In 2004, an effort was started to move to a more "modern" microkernel. L4 was the first and it died almost immediately. Work started toward the Coyotos microkernel, but between 2007 and 2009, focus shifted to Viengoos. But then "As of 2011, development on Viengoos is paused due to Walfield lacking time to work on it. In the meantime, others have continued working on the Mach variant of Hurd."