There is talk of up to three apps open simultaneously and support from Google for devices that will use this technology. The folding Samsung should see the light in 2019, no one knows at what price range. It is supposed to be high, since it is an absolute novelty.
It will be necessary to see if there will actually be a market for this smartphone / tablet and if it will bring advantages in everyday use compared to non-folding competitors. The ball goes to Samsung. We just have to wait.