In the mid-range and treble the design and number of drivers determines the ability to play loudly, but enclosure size has no direct influence(has to be big enough to hold the drivers, of course).
And this is why i went with the M60s over M22s.
They just didn't fill the room with sound.
The larger speaker does that much more effectively.
I'm not sold on this recurring idea that M22 plus sub sounds like a M60/M80 either. For the record.
Aside from a vastly different driver size on the sub. vs the tower speaker drivers, most may not locate the M22 right on top of the sub so you now have a location change with this pair compared to the tower speakers that have an 'all in one' location.
We started with M22s and a sub WAYYYYY back when. Still had the M22s when the M60s arrived.
It was a long time ago but my recollection of this comparison was that it wasn't so similar.