If I'm not mistaken "lady" was and remains (at least in the UK) a proper form of address for both members of the gentry and the nobility with the exceptions of a duchess (your grace / duchess) or a dame (dame). Whereas gentleman refers only to members of the landed gentry who rank below baronets, knights, and esquires. So in a strictly noble context "lords and ladies" would be appropriate whereas if applied strictly to members of the gentry "ladies and gentlemen" would be accurate. In the US the latter is common while the former is not because we have no acknowledged titles of nobility and qualifications for the status of "gentleman" are a bit vague. So it's an acceptable assumption / compliment.

tl/dr In places where there are still lords it really didn't change