Those are a thing in the US and ridden by adults and teenagers alike. Not ridden as much as cruised and posed. The one in the photo is an off-the-shelf one but there are people who make custom lowriders and cruisers and spend an awful lot of tie on them too. Some makers are incredibly skilled and every single component on the bike is detailed to the nth degree. Spare a thought for the poor wheelbuilder who has to lace 140 spokes and then somehow turn a spoke spanner within the small gaps between spokes.