It's not that simple. There is more to a game artist's job than just creating a generic model and texture. The art has to be in a specific art style, it has to be within a certain budget, it has to be made in a certain way to work in the game engine. The textures have to be made to work with the shaders that it will be using and look good in the game's lighting system. Physics might need to be setup. Destruction states. Lightmaps generated. It might need to be created so that it can be rigged and animated. There are places like cgtextures.com for textures, and there are artists who turn those textures textures into the art you see in the game. You can't replace the game artist.