True archtop guitars are notoriously short on fundamental, I can't imagine an archtop bass guitar that could compete with the flattops.
That depends on body size; those old jazz (blues) boxes are tiny. In theory, the closer to a sphere (arched top and back) of large enough size for the wave to form (1/8th wavelength of 40 Hz is still pretty big) it would perform vastly better than a flat top as regards fundamental resonance/projection). Seeing as that's not easily done (though some guitarons, many with arched backs, come close), yeah, often flat top is the better way to go considering cost. Put arched top and back on something of Earthwood size and tell me it doesn't sound huge.
Anyway, the archtop comment was more about a hole I saw in the current market offerings, a stream of consciousness tangent from the bridge discussion. Though I do believe (as long as the market weren't saturated, which it certainly isn't, but instrument makers tend to the domino effect) they would sell, middish, jazz/blues vibe or no. Especially because you could, due to it 'working' aesthetically, also put a real pickup in it without it being weird (a la proper jazz guitars) vs a cheap (in every sense of the word) piezo system with the same old tired Fishman preamp.
The bridge thing is something I actually think is a very simple improvement that could make a budget ABGs (even/especially flat tops) exponentially better (if they leveraged it to make the top better acoustically - thinner, not overbraced etc), and the much more important point.
