Meads sweetness is entirely dependent on how much honey you use. Based on my readings, everybody before modern times prefered wines and meads on the sickeningly sweet side.
But generally wine would be aged in barrels, not in expensive glass bottles.
Not more popular, given that there definitely existed a thriving trade in wine from the Med/France northwards. I’m not aware of a reciprocal mead trade Southwards.
It’s not really apt to compare mead with wine in those locales - the question to ask is if it was more popular than ale. Which varies from place to place, I think, but certainly mead was the in-drink in Scandiwegia. Not just for its alcoholic content, but also its religious/culturalsignificance.
Say you walk into a Roman bar for wine. Do you get a selection or reds, whites, varieties “this new batch of Gaul stuff is pretty good”, or just order “wine” made with whatever grapes were around.