You're right that in the consumer audio industry you often don't get what you pay for. I suppose as long as we're all happy with our own purchases and that they achieve our individual goals with regards to what the sound system does, then it's all good.That depends entirely on your criteria. If it's 100% performance then you absolutely don't. There are equal or better performing subs for a fraction of the cost of this sub. Go the DIY route and it's an even more stark difference.
I'm lucky in that in my cinema (almost done!!!) I have the luxury of not needing to care TOO much what it all looks like. For that reason I've managed to shoehorn 2 full marty subs with UM18-22 drivers in. I will comfortably say they will wipe the floor with this sub in almost every conceivable possible measurement and metric. I can guarantee you they cost me under half what this cost.
On the other hand, if you are after a very specific size or aesthetic then it may be worth the extra money to you but for me that's a huge price delta that I would never be prepared to pay. If you're happy with it that's all that matters ultimately. I'd just be wary of perpetuating the audio industry bull of "you get what you pay for" as in the audio industry, more than any other, this couldn't be further from the truth in most instances.