The Warriors did not offer Baron more money. They offered a two year deal worth $28 million. The Clippers signed him for a five year deal worth $65 million. He wanted a long term deal and Mullin didn't give it to him.
As for Gilbert, the Wizards initially offered a six year deal worth $100 million. Then the Warriors offered a five year deal worth $100, so the Wizards topped with a six year deal worth $126 million.
It's a sad day to see Baron go, and also to realize that the Warriors are going to be below average(unless something happens). Mullin is a horrible decision maker and really screwed the team over by not working harder to get a deal done.