Re: And another confusing point
I guess that prediction is based on being able to achieve sufficient pressure at room temperature
That's my understanding too.
The article refers to pressures of approximately 200 GPa at around 1000oC. At room temperature a proposed metallic hydrogen precursor has been created at a pressure of 384 GPa, so we have some idea of the even more mind-boggling pressures required to achieve room temperature metallicity.
Nature magazine abstract: https://www.nature.com/articles/nature16164