I think the paradigm has been lost, at least for major phone manufacturers, to design or produce anything but thin glass slabs.

The N900 even the N950 are small chonkey devices with physical keyboards, is there even a supply chain anymore for the slider rails these phones use? I feel like this kind of thinking is left in the past like 'dumbphones' and not up for consideration for flagships which are for surfing social media and Netflix; screen area for popping the 1080p video to as large a size as possible. These are movie rectangles not portable computers, the opposite of the N900 and N950 which are computers which can play movies if you need that.