If i were BUYING a ready made speaker i'd agree with you completely. The amount of care the manufacturer has out in the cabinet is important. OTHO, the drivers in many commercial speakers are not more than a small fraction of the askng price. However, if we are BUILDING a speaker, and one has a LIMITED budget, then i'd pay more for a driver and maybe compromise on the fancy finish (stain it yuourself, skip the burled walnut...simply settle for 3/4 baltic birch, don;t get the joints dovetailed); or i might get a better driver and pay less for a simpler BR cabinet versus a complicated horn....
it;s all allocation of budget. Anyways, i think we all agree...we are just talking of different things being right in differnt situations.
-akhilesh