I think everyone would like to believe that a budget sub or speaker is going to produce the same results as say a 'reference' type system.
And in some situations I suppose this could be accurate.
But when you get right down to it; high quality speaker parts or any type of high quality parts regardless of the industry are expensive. Drivers, enclosures, everything adds to the final costs, including the finishes.
To get high quality low distortion parts requires more money than a budget product will allow. Higher distortion parts whether its the driver or the enclosure will contribute to the sound and take away from the quality of the system. And that's not saying anything about the engineering that goes into a given design. But lets assume for this example that the engineering in both a budget and 'reference' level speaker were equal.
If you want truly high quality low distortion parts and low cost you have little choice but to build the products yourself, saving the labor and high expense materials (like a well built box).
I'm not saying a person has to go 'high end' to get good products, just that to compete at the same level you have to put the same 'level' of parts, engineering, and build quality into the product in order to actually compete with it.
You shouldn't be able to compare a 400.00 sub with one that costs 1k or 2k. If you can, then something was missed in the design process and/or the decisions made for the parts said product includes.
There are other factors too; like the retail markup that certainly can hurt some products. Retail markup is in the neighborhood of 30 to 50% in most cases. If a company can eliminate this markup step it should offer more performance per dollar than a system that is bought from a store where the overhead can be immense.
Again, this is not an indicator of quality, but with many companies going to a 'direct' sales approach its becoming more difficult for retail chains to compete. This is why many of the retail offerings include parts that are less than 1/10th the cost of the product. Cutting 40% off the top certainly makes more room for using higher quality parts into the design at a given price. The downside is that there's not as much marketing (compare to retail) advantage to back up the speakers or the companies claims. Nor will the company reach as high of a market acceptance because you'll never see them at the Big Box store or even a high end retailer for that matter.