Sound is a very subjective matter and it deviates from different perceptions. True, the number of drivers does not determine the sound quality or rather it should be the tuning that is important.
But what if now Westone decides to release a similar 4 drivers "W4" but with different tuning rather than a 6 drivers with different tuning? Many will be commenting that Westone are not keeping up with the current trend and the market. The IEM market is closing in at a very fast pace with no really true, innovative or revolutionary technology (example for the past, hybrid was a new thing), hence the only way to capture the market is to intrigue and infuse consumers with idea of more drivers being crammed into a single unit. Will it be better for Westone for example to release a different tuned 4 drivers IEM and charging lesser? Well, to me no. As a market leader in IEM and in order to sustain their market share, most companies are determined by the size of their balance sheet and the wide number of products they carry to plug the gaps (example, P&G, Unilever), going with more variety like 5 drivers and 6 drivers would probably be the best option now.
Psychologically, people will be more willing to pay for "more drivers" rather than a similarly priced single driver unit. The thinking that "2 is better than 1" prevails. With rising pressure from more companies releasing >6 drivers as their new flagship, Westone have to hop on the bandwagon. Conformity will set in with consumers willing to pay a premium for more drivers opposed to few drivers due to lack of new innovations. Cognitive dissonance will drive the mind that since I'm paying a premium for a product with no new technology, I will be generally better off with something "more". Diminishing return with a drop in utility will set in with the outlook of stationary or even decreasing margin. Thus, with the lack of innovations, you have to depend on more labour (in this case, more drivers) to do the job to sustain and grow.
However, this is not all bad as we will see the reach of a saturation point where consumers will stop the chase and prices will have to fall. Just like the smartphone race to release a new model yearly with few new softwares implemented. But do we really use those softwares? But we end up paying for them. Just like Samsung reported a loss in profit due to slow mobile growth.
"You can fool all the people some of the time, and some of the people all the time, but you cannot fool all the people all the time" (Abraham Lincoln).
I believe we will see true new innovations in this year 2014 as some companies are already using their own proprietary drivers as they will come to realize that this is not just merely about a race of the number of drivers. Westone may have entered the bandwagon of drivers or race albeit slightly late as consumers are already being bombarded with releases of 6-12 drivers flagship since Q4 2013. Maybe Westone should have took a leap with a hybrid implementation which may be more appealing and interesting. Hopefully the market this year will bring new surprises to us, consumers!
Nonetheless, it has been interesting to see companies springing up new releases and Westone which has always done well with BA drivers to introduce new products!
*Just my two cents worth.