Unfortunately, the public's ability to be oblivious of picture quality is advancing LCD at the expense of the superior plasma technology. Even Pioneer is starting to wonder whether people really care about picture quality. (Right now they can't make enough of their Kuro screens, and that's a good thing. But the prices of flatscreen LCD are forcing them to cut the price of the Plasma screens, as well as cut back on planned production capacity.)
An acquaintance of mine has produced 20 feature films. You couldn't push an LCD screen on him with a shotgun. He's got a B&O CRT, "because that's the best thing out there." He's eyeing plasma, though.
As to backward compatibilty - there are good scalers that will take DVDs up towards the HD levels (though not matching them, of course.)
And as to SED. Nano Technology got greedy, as they too thought SED would be the next big thing. Canon and Toshiba had the production muscle. By pulling the plug, they are telling Nano to say goodbye to all that money. Which means Nano are sweating now, and might come back with a better offer. (They had a proprietary patent.)
But with the drop in flatscreen prices, I think the Philips director quoted above was right - it won't be feasible to launch a new platform.