In 1977, before the discovery of high-temperature superconductivity, V. Ginzburg wrote:
“On the basis of general theoretical considerations, we believe at present
that the most reasonable estimate is Tc300 K, this estimate being, of course, for materials and systems under more or less normal
conditions (equilibrium or quasi-equilibrium metallic systems in the absence
of pressure or under relatively low pressures, etc.). In this case, if we exclude
from consideration metallic hydrogen and, perhaps, organic metals, as well
as semimetals in states near the region of electronic phase transitions, then it is suggested that we should use the exciton [electronic] mechanism of attraction between the conduction electrons.
In this scheme, the most promising – from the point of view of the possibility of raising T-materials are, apparently, layered compounds and dielectric-metal-dielectric sandwiches. However, the state of the theory, let alone of experiment, is still far from being such as to allow us to regard as closed other possible directions, in particular, the use of filamentary compounds. Furthermore, for the present state of the problem of high-temperature superconductivity, the soundest and most fruitful approach will be one that is not preconceived, in which attempts are made to move forward in the most diverse directions.”
I took the quote out of this paper here, though many of the ideas are echoed from and better expressed in one of his previous papers, linked here. It is amusing that for at least 15 years prior to the discovery of the cuprates, Ginzburg stressed looking for high-temperature superconductors (with Ts above the boiling point of liquid nitrogen) in layered, quasi-2D materials that could host superconductivity with an electronically driven Cooper pairing.
The papers linked above are very readable and he reached these conclusions on startlingly general grounds — by discussing the inverse dielectric function.