Liddle (2015, p.67) writes: "From the crude estimates that a typical galaxy weighs about $10^{11}M\odot$ and that galaxies are typically about a megaparsec apart, we know that the Universe cannot be a long way from the critical density."

Was this fact (i.e. that the actual density is likely close to the critical density) known from these crude counting estimates in the 1980s before the CMB precision measurements in the 2000s confirming flat geometry? If yes, does anyone have specific references to papers providing such crude estimates before 1990?

Reference: Liddle, A. (2015). An introduction to modern cosmology. John Wiley & Sons.