Another thing to consider here is the old astronomer's bugaboo: selection effects. Some kinds of binaries are easier to detect than others, for example, a distant companion will have such a low orbital velocity that it can only be detected because it's proper motion resembles that of it's primary. If the binary is a close one, the fainter may be swamped in the glare of the brighter. Spectroscopic binaries rely on the members of a pair being so close that orbital effects allow their spectral lines to split, but this only happens if the orbital plane is in our line of sight, it's a cosine theta function of the orientation of the plane to the celestial sphere.

Close binaries would not necessarily make a planet impossible, but the habitable zone might wind up so close destructive perturbations in the planet orbit could be set up. And if one of the stars is more massive than the other, it will evolve much faster, perhaps faster than life can tolerate.

But if old stars are now thought to be less likely to be binary, that is good news for astrobiologists.