You are just not going to get a ton of 304 stainless at this price point. I am glad they used higher grade for the warming rack. Nice to have one you won't have to trash in a year after it rusts out!
These are not grills you are going to leave out in all the elements year after year. If garage kept, and well maintained, though, these - and newer Webers for that matter - I think CAN last a decent amount of time.