That's 24 guys you listed with better records than Hurney. And that's not even counting guys who just recently took over as GM, like Reggie McKenzie who was director of player personnel for the Packers and won two Super Bowls with them before taking the head job for the Raiders this year.
And then there's this...
Cinci's GM is also the owner so he's not going to fire himself and Arizona is just retarded. In general teams don't let guys hang around as long as Hurney if they can't put together winning teams, especially when their results have been declining (try bringing up the winning % for the last 5 years).
Your post actually shows definitively that we SHOULD get a new GM, not the opposite.
Spielman and Allen are still in the nfl. their current win percentages are terrible with their new teams.11 of the ones you mentioned I already stated were better than Hurney based of record.
That leaves 9 that you need to look at in the proper context. Jones in Dallas and Peterson in Kansas were their for 20+ years and had rode some nice waves but recent history is not kind to them
Now we are down to 7 and in the proper context(length of employment, divison,etc.) they are not any better than Hurney or even still in the NFL