Speed versus Size
In order to make the transistor so small, they had to use a material with lower electron mobility. When there were news items about the experimental world's fastest transistor, materials like Indium Antimonide were used, which had a very high electron mobility.
If we made computers with 1nm transistors instead of 20nm transistors, but they ran at 500 MHz instead of 2 GHz, I don't think very many people would be interested. So that, not the fact that it's just a prototype, and they're not ready to make a Molybdenum Disulphide microprocessor just yet, would seem to be the killer.
Biting the hand that feeds IT
