There are a larger number of small players, full stop.
I don't think I understand what you are driving at.
Bose has a long history, patents, serious R&D (or did at at least one time),likely an anechoic chamber (those aren't as common as you suspect),pedigree'd engineers, and a huge emphasis on form.
Many of the small players in the market assemble in their home towns, provide detailed product specs (including links to where yo purchase the same driver),and offer both first and third-party measured specs.
Of course: there are also great large brands and terrible small ones... again, I'm not sure what you are driving at.
Though pretty much every established brand was an upstart at one point. I recall the first mainstream products from SVS, Hsu, Emotiva, Oppo, etc.
Let me be blunt then... There are a lot of bit players in the business that don't have the parts to produce quality loudspeakers.
WRT Bose, you answered your own question... "form" is a principle design criteria for Bose products, not sound. That's why the company is famous (or infamous) for not publishing specs for its products. Doing so would not necessarily be in that company's commercial interests.
Bose's R&D has largely been focused on psycho-acoustics, which is a field of study that is not universally accepted by audiologists and sound engineers. While Bose has done well in this field (they sell lots of stuff and apparently make lots of money), nobody I know would accuse them of reference quality sound. At least not in the strictest scientific sense.
Your point on anechoic chambers is well taken. Far too few manufactures have these, which explains in part why so many manufacturers can't seem to build a neutral sounding speaker. This could be a big problem as bricks and mortar stores give way to direct sales but manufacturers got around this by advising customers that speakers need to be broken-in (which is largely nonsense but plays on a principle of psycho-acoustics that says that people's ears need a short time to adjust/compensate for differences in levels and sound quality).
As for specifications, I looked up the two brands you mentioned. Their web sites don't contain the kind of detailed specs one needs to assess whether they are good, bad, or indifferent. This isn't unusual, many of the big players don't either but will provide if asked. The reason why they can provide is because they spend a lot of time measuring and refining performance in a lab environment -- something small players cannot always afford to do.
[I'd be delighted if you could point me to a link that shows unsmoothed frequency responses, spectral plots, impedance and phase curves etc. I just love reading these things and am always on the look out for excellent products.]
Your point about everyone being an upstart at one time is more or less correct. But the companies you mentioned didn't start producing and selling speakers at $3k and up. They started small, built knowledge and expertise, and then entered the higher performance market. Some of them started small before being swallowed up by large companies with the budgets andknow how to take their products to the next level.
The reason is because it takes time to build the depth of experience and knowledge needed to make an excellent product. This is a truism that exists in just about any technical field, not just loudspeakers.
The "home town" issue is an example of pure marketing BS. Within certain bounds (child, slave labor) I don't care where a product is assembled. Neither should you.
The truth of the matter is that just about every product today touches the global supply chain at one time of another.
Some companies try to make points by portraying themselves as a group of artistes, assembling products to the sound of harpists and all sitting down for lunch together. Reality is often very different. So if the cabinet maker is a chain smoking, self-taught dude who nips out for a beer and tabletop ballet half way through his shift, who am I to care if his products meet muster? Ditto for skin color, ethnicity, nationality.
Companies would do well to spare us the glossy brochure featuring the gracefully weathered face of a model portraying a European craftsman staring down the edge of a finished joint. But if a company doesn't have the independently verified specs to back up their performance claims, then a glossy brochure will have to do. I guess.
If you have exceptionally deep pockets to build the right facilities and hire a helluva lot of talent, I suppose one might be able to offer a high quality loudspeaker in fairly short order. Doing so is far rarer than registering your company name, hiring a few talented wood workers, buying some d rivers and claiming to be a high end manufacturer. There are too many companies out there taking this approach, and it's neither good for audio nor good for audiophiles.