Do Bigger Speakers Mean a Bigger Window?

I enjoy listening to small loudspeakers, in fact a lot of my listening is done via my Logitech desktop computer speakers (2 SATs + 1 small sub) or those in the car.

However ultimately there's nothing like the sense of ease of listening via a big pair of speakers such as big Harbeths, vintage JBLs or Tannoys etc.

I wouldn't say that the bigger speakers (8 inch+ cone) are more accurate, in fact the Logitech's have an uncanny way of getting voices stunningly right as  
watching home movies on the PC demonstrates. It's just that the larger loudspeakers seem to reveal more of the recording quality and bandwidth. So much so that sometimes you can easily hear the limitations of the original tapes sometimes.

So, if you are after high fidelity sound, why would you buy small speakers?