Ossoff's strategy of running on ending government waste seemed phony to me. Sure, the attacks on him for being a "San Francisco liberal" were just as bad but calling for an end to government waste isn't promising much. Every politician promises it but there's not much to cut. It doesn't get to the core issues of the country. He ran on nothing and couldn't win over people who might have given him a chance. Of course, in a district like this it would be hard to run on Medicare for all and increasing taxes on the rich. It will be hard for Democrats to win districts like this which are exclusively white, rich suburbanites, especially if they voted for Trump. They will do better to stick with districts that have either more minorities, college students or working class folks who can be won over with a more traditional Democratic argument.
Usually because they ignore the part of the government that probably has the majority of the waste, the Department of Defense. Well, certainly the majority if you exclude healthcare.