That is a bunch of bolony! The differences are getting smaller and smaller, but there are still lots of them.
First of all, the action is usually completely different. Most digital pianos don't have an escapement mechanism. There are some however (Yamaha) that do incorporate a true acoustic grand action (very expensive). However, is an escapement mechanism really necessary? That's a different question, though.
Even if you had a real action, the sound that digital pianos produce is far from the real thing. This has to do with the limited amount of memory in those devices, which does not allow to store realistic samples. The best one can do is to connect a digital piano to a computer and run some of the high-end digital sound samples on it (takes up up to 5 GB of memory). In this case, the sound can get pretty realistic.
However, no easily accessible digital piano at the moment comes close. The only one, perhaps, is the Post Piano. Definitely not Technics, which by the way, as far as I know, has gone out of the digital piano business. Perhaps, that's why he was pushing so hard.
It is best not to think too much about the similarities and differences between digital and acoustic pianos. They are both musical instruments in their own rights. Digitals are great for practising, recording, exchanging music, playing around with different instruments, composing, etc.
And imagine, all those tuners would have to find new jobs...