A few things people need to realize.JL audio is a business, they are there to make money.If most people are willing to pay $600 for whatever it may be, why make them pay $200 ? Why turn down profit just to make a *****y little internet community or other cheap people happy? They know what their product is worth.And obviously they aren't doing bad, and do not have any problems selling their products.
And a lot of people I know that are into car audio are incapable of building their own enclosure.Sometimes they'd rather spend the time with family, or they might have work.Whatever the reason.It is not wrong for someone to buy an enclosure.