So, the discussion appears to be all about looks. Can the DIYer build as nice a piece of furniture as the pro speaker companies? I have not seen much in the discussion about the performance and how DIY results compare to the manufacturer's products. I am a DIYer and can offer the following comments about the speakers I build, I have not had a commercial speaker in my main set-up in over 20 years.
1. My speaker builds look like crap compared to the manufacturer's products. You need to recognize that exotic looks take money that could have been invested in the sound, looks do not produce hi-fi. Looks appeal to the eyes not the ears.
2. I believe, and others who have visited and listened to my set-up over the years seem to agree, that my most recent designs are very competitive with commercial products. Like a commercial design, some like the sound of a design and some don't. At some level it becomes a matter of personal taste.
3. By going the DIY route I can design and build something that is specifically entended to work in my room (no compromises to fit all possible rooms in the market place), my taste in sound, and my associated equipment. I can modify and tweak to get exactly what I want.
4. I can build something out of the mainstream that most manufacturers in their right mind would not bring to market such as large dipole systems, TL speakers, or back/front loaded horn systems. You will not find these designs in many BM locations near you.
5. I can reverse engineer just about any manufacturer's design if they use commercially available drivers, provide external dimensions of the enclosure (even a picture will do), and even better if they allow Stereophile to publish details of the design and measurements in a review.
6. Designing speakers is not rocket science. IMO you need an engineering background, some software, a measurement set-up, all coupled with some understanding of what sounds good.
In conclusion, my builds are not the high quality furniture which is important to some people. I believe for a fraction of the cost I can build a competitive speaker system based on sound only, some will agree and some will disagree after hearing or reproducing what I have designed and built. I don't care so much about how it looks, I care only if I like the performance. My speakers are unique, not copies of other designs which is the fun in the hobby. I do not need to spend tens of thousands of dollars to get what I want and like in a speaker system. On the other hand I don't look to build the cheapest speaker possible which I think is the down fall of many DIYers. Spend the money, learn the theory, build and learn, enjoy the hobby.