Here is my .02, although many Orchidians have already offered thoughtful and accurate counsel above. Keep in mind, our company specifically does not focus on anything but one-off custom (rapid prototyping), so I can't speak intelligently about competing with the type of product offering you describe, I can only speak about what I know from firsthand experience, which is custom.
So - this is what I personally have figured out after several years in this business. I know some of it sounds obvious, but I am not the sharpest tool in the shed, so it was not obvious to me until I actually got cooking.
1) If you sell low-priced stuff, even if you sell it at a high margin, you need to sell a lot of it to make any money.
2) Today's consumer wants higher quality, more personalization and selection, at a lower price, with better service, served up in a business model that fits their needs. They don't want one or two of those things, they want all of them.
3) Relationships drive value in the jewelry business. That's relationships with suppliers, with customers, with manufacturers, and with employees. Real relationships take time to build.
4) Jewelry manufacturing (the process of making a truly high quality product) is NOT a commodity skill. Orchid exists quite literally because manufacturing great jewelry requires a lot of experience. Like many things in life, lots of people will tell you they can do a great job, but lots of those same people cannot do even a good job. To understand what "great" looks like requires a meaningful investment of time to gain requisite experience. One cannot "stand for quality" if one does not know what quality looks like and what the drivers of quality are. If one does not stand for quality, one will not be in business very long (see #2 above).
Now with all that said, I do think this is a GREAT industry, and one where there is still tons of room for innovation. I am dedicating 100% of my time to the industry for just that reason.
I hope any of this is useful, and I do sincerely wish you the best!