I work in the bridal business and wanted to make a few points, I don’t want to offend but I feel your video is one -sided and over simplified.

1. In my experience bridal gowns are rarely mass produced, far fewer are sold than other types of clothing ie jeans etc, so they are not made in large numbers, also often they are not made abroad so labour is dearer. I do work a little differently to how you describe, which I would like to explain,
I would not have my gowns made in China as I fear that workers are exploited, so I pay to have them l made locally at a cost of aprox $450 to $550 per dress, sometimes more, that is only for the labour -then hand finished by myself -which can take six or seven hours. I then have an appointment with the bride to try it and resolve and fitting issues so that can add up to another days work. I also pay for silk covered buttons, and beaded trims, and possibly other extras.
I notice your lovely dress has a zip and buttons on top, I would for example not do that as it is a short – cut. If so what about local taxes/ import duty/delivery costs etc, I have friends who do have their gowns manufactured in China and say the extras all add up.

2. Direct cost of sales – with commercially produced dresses – as well as the cost of manufacture and fabric there is also the wages of the sales assistant and all the shop over heads, I assume you visited several shops and tried gowns on, there is a very real cost to the shops each time a bride visits; light/ heat /marketing/ packaging/insurance and cleaning costs etc.
Also major cost such as rent or mortgage/ business development loans repayment etc.
Many times a visit or even several visits by one bride does not result in a sale, so shops have to take that in to account, Shops may average one sale in eight or nine or even ten appointments, and then the sale may require further visits it is rare for one visit to create a sale. You also have to ask yourself how much you earn per day and then think about the shop staff do they work for nothing ?

3. On going pattern development and sample making, someone made the pattern and possibly several fabrics were tested and several proto-type dresses were made for each design, pattern cutters and sample makers again do not work for nothing. I plough a lot of my profit in to improving fit and testing new styles and fabrics
.
4. Hidden costs – all manufacturers have their products photographed which is one of many hidden expenses a model /makeup artist /photographer/ studio /prop hire is not cheap. Fashion shows /trade shows /website development /SEO/ magazine advertising/ blog adverts
all have to be done, Accountants have to be paid also book keepers ‘admin staff for large shops etc. Tax also has to be taken in to account.

4. Polyester is a good fabric, it is cheaper than silk of course but never creases which is important, and hangs very well. Sometimes I cannot find the right weight/colour of silk and use the most suitable fabric wether it is polyester or silk. For example I have observed that top Designers (for example Alexander McQueen ) sometimes use polyester in their evening gowns and line them with silk. Silk is a somewhat ‘unkind’ fabric -the silk worms larvae are destroyed in the process, and in my opinion should be used where appropriate not just for the sake of it.

5. Many workers are involved in the bridal trade and all have to make a profit – to keep going, the alternative is to buy online which involves no service do you really want to boil the experience down to it’s barest minimum like buying a loaf of bread?

6. I charge around $2000/2500 for a dress but actually work six days a week and make very little money as I give a lot of help advice with accessories /underwear/ etc and general service, brides are always lovely, but can be quite demanding and are not always easy to please. One dress sale can involve five or six visits and accommodating quite a few family and friends making them tea etc, which all takes time and energy. Apologies for going on a bit -just making a few points and I hope I have not given any offence