Perhaps for people in the US, but this would be elementary school arithmetic in Europe.

I’m European and I’m extremely sure that when 90% of people hear "x m^3" they don’t think of it as "1000*x litres". And the majority of people likely can’t recall on the spot that 1 l = 1 dm^3 (a unit nobody uses), even if they remember that you multiply by 1000 to go from m^3 to dm^3. In any case most people don’t do conversions like that unless someone specifically asks them to.

Volumes are in general very unintuitive to people due to the cubic scaling. It’s further confused by the fact that the widely used decilitre, centilitre, and millilitre do scale linearly, unlike cubic metres. So 1 l = 1 dm^3 but 1 dl = 100 cm^3…

I don't know where do you live but even my small nephews and nieces understand that a 1 meter cube of water is A LOT OF WATER, because mentally, we have lots of 2 liters bottles to compare it to

Sure. But the average water use per person per year where I live is in the tens of cubic meters. So 1000 cubic meters per year isn't that much.