I was with you up until "all third-wave beans are lightly roasted". I suppose it's literally true relative to old espresso roasts, but there's still plenty of third-wave roasts that are decently dark. Maybe not Folgers/Lavazza dark, but you can definitely find more oily/heavy roasts that aren't overly acidic.
There's also a third axis in brew technique - most old-school espresso is only vaguely the same brew method as what you'd get at a third-wave shop where the newer machines have fairly precise temperature, flow, and pressure controls, as well as more consistent grinds with less fines.
There's also a third axis in brew technique - most old-school espresso is only vaguely the same brew method as what you'd get at a third-wave shop where the newer machines have fairly precise temperature, flow, and pressure controls, as well as more consistent grinds with less fines.