Typical Dell nonsense, but what more should one expect from a box-shifting outfit.
Also the usual backwards thinking from many, with a "must have backwards compatibility" starting point.
The big issue I have with the cry for backwards compatibility is the fact that this new machine has a fundamentally different hardware architecture to that which current OSs were designed for. It's an opportunity to think again - to come up with something new that can best exploit the new architecture, rather than forcing an old paradigm to work.
To best exploit this new hardware architecture everything needs to change, and one will need new software architectures to do that. When what you have is a machine that essentially has a massive amount of persistent RAM and no disc storage concepts like "booting", "starting an application", "saving a file" or even "disk filing system" can go out the window, as does issues like "seek time" and "disk latency". Carrying those over from a legacy OS will just bring inefficiency with them.
Of course backwards compatibility is important, but the way to provide that is with virtualisation/emulation. Machine OS could provide a virtual environment to a *nix OS that looks like there is a regular disk and memory system. It would be very sad though if that's the only way to run software on such a system, as most of the benefits would be lost.