G-dwarf problem

The G-dwarf problem is that fewer G-type stars with low metallicity are observed in the Milky Way than theories of galaxy formation and evolution imply there would be. G-type stars have a sufficiently-long main-sequence lifetime that early-generation examples with low metallicity should still be present. The problem is also detected in K-type dwarfs and M dwarfs, but I speculate it stood out more with G-dwarfs because they are brighter and visible and analyzable through more of the galaxy, including regions where some with less metallicity would be expected. Some observations of other galaxies suggest the problem is also present regarding them.