Demongornot, the problem is, that you can't change such a technology like flipping a switch.
Currently, we have a rock-solid house built upon a nice basement. Yet there is no cellar. Of course, there are houses with a cellar. Even houses from Microsoft with a nice, giant cellar. People told you it's possibel, even with different rooms, but still this ED-house still has none.
Now the problem is, that this is not a new house. It's a big old house and there are a lot of different things to consider. And you can just lift that house up, build a cellar and put it back on top. It simply doesn't work this way in our physical world and neither does it in software-business.
If you want fundamental changes, you either need a lot of money and manpower and build it from scratch. Or you have to do it with one step after another. And that's exactly what they are doing.