Go back and reread what I said: compare an acoustic archtop guitar to a flattop of the same size and the flattop will easily have more fundamental. And size for size, it would be extremely rare to find an archtop with as thin a top as a flattop.
How about you read what I said, eh? Show me an archtop of comparable size to a dreadnaught. The only ones I can think of are a) not actually proper acoustics (i.e. sustain block + cutouts in the top for standard pickups) or b) 5K+ boutique jazz guitars which neither of us are likely to ever get our hands on (and with these I am not sure they are similar size; just looks like it on the internet).
Sure, the tops won't be as thin as some better flat tops, but are often carved from a single solid piece; more than makes up for it (glue, i.e. constrained layers) between the plies deadens the sound much more than a few extra mm of wood will.
You clearly don't know enough about design to know whether or not an Earthwood with a solid arched top and back would be bassier. You also don't understand why archtops use the typical bridge and trapeze tailpiece vs. the flattop bridge, or else you wouldn't have wondered why ABGs don't use them. There is a lot more to design that just substituting a different type bridge or substituting an arched top.
Ouch. Don't be so condescending; doesn't look good on you. Especially when this is not rocket science.
I know why the different bridges are used; it's predominantly down to not having enough flat surface area on a archtop to mount anything else but a floating saddle (nor enough depth of wood to use something screwed or posted in). There's no reason not to use a trapeze on a flat top guitar (and in fact I have seen flat top 6 banger acoustics with trapeze tailpeices often.... just not basses). This was all thought out centuries ago and tradition/expectations (as well as certain people being fetishists about one or the other sounding better) have developed over time.
There's a reason arched body upright basses have a lot of bass: they have huge bodies to move the needed amount of air. The only way to get even remotely near that with the guitar-sized body of an ABG is with the flattop designs that exist. If archtops of the same size could get an equal amount of both bass and projection as the flattop ABGs, you can bet the market would be full of them.
The market argument ignores one reality I have brought up repeatedly: production (and therefore retail) costs. Archtops are more labour intensive to make. So nice non sequitor there. You make this argument all the time so I have to point out that lack of something existing on the market means nothing other than it is not (in a production company's point of view, which may or may not be correct) economically feasible/sustainable to produce. It does not in any way indicate that what does exist is better; merely overall more actractive/easy to sell, which is not the same thing. History has shown repeatedly that pricepoint is a much more significant factor than "betterness." It's like someone in the 20s saying that metal edges on skis are not superior because they don't exist on the market. ... oh and archtop ABGs do exist (but are really expensive) so game, set,and match on that score (see link provided by someone a few pages ago).
Otherwise, this is exactly what I said. More volume (in the mathematical sense of the word, not in the auditory one). Now it is you who is knowledge deficient (though physics/geometry vs 'design'.... also economics as mentioned above; glass houses) because if you have 2 bodies of IDENTICAL SIZE, put a flat top/back on one and arched on the other. Which one has the larger volume of air inside?
NOT the flat top.
Arched top/back make a body bigger (are you assuming that the underside of an archtop is flat or something? only on shitty ones or solidbody archtops).
And indeed I have been saying that ABGs, to be more acoustically useful, need bigger bodies than those designed for use on a 6 banger tuned a full octave higher. Granted, just adding an arched top/back to the same size body won't get you there, but it won't hurt either (barring other factors I have mentioned). That is all.
