George, I might agree with you if Lionel licensed the LEGACY sound and control package to the likes of Atlas. But I absolutely disagree with your assessment if Atlas continues to use TMCC with the very dated and very generic RailSounds packages. I don't know about you, but a lot of us here aren't very excited about purchasing $500, $600, or $700+ locomotives with outdated (and often incorrect) engine sounds...even if they do have TMCC control. Certainly not with what's available with Legacy or PS3 today!
I own several Atlas locomotives, from some of their early stuff right up to their most-recent releases, and the sound packages are terrible when compared to current Legacy or PS3. They were fine way back when Atlas first started using them, but they simply don't cut it today.
I don't know if you own any Atlas TMCC/RailSounds and MTH PS3 locomotives, but if you do, I urge you to run them one right after the other. I'm confident you'll agree that PS3 blows the RailSounds away...without any doubt whatsoever.