Like Ryan said about cars, There are also different design philosophies wrt cabinets... some will build a stiff, light cabinet with minimal damping and very high resonant frequencies that are unlikely to ever get excited. Others may go for a heavy, mass damped cabinet. In pro audio, where stuff is moved around a lot, the stiff/light designs are obviously the way to go but for home use there are examples of all sorts of cabinet designs. Like anything it's all about implementation, there is no right answer and good sounding examples of very different designs do exist...
The Focal at ~$9k doesn't have a light cabinet because they are trying to save $20 on mdf, it's the result of their design philosophy. and there is also the fact the Salks go ~10 Hz deeper and probably also have greater low bass output as well.
This thread is a great reminder that a speakers #1 priority is to look good though.
If it doesn't look good folks won't even make an effort to listen to them.