At a first glance, anyone could think a motorbike consumes less than a car but this is not entirely true. A bike, with a weight of around 200 kilograms could be more expensive —polluting more, that's the point— than a car with five times this weight or more.
Specially in motorbikes of the last decades, it's very common to see 600cc bikes with consumptions of 7 liters per 100 kilometers. At least, there's a model Golf 2.0 TDI with a surprising consumption of 3.6 l/100 km in the road.
Was the motorbike industry worried about fuel optimization? How is this possible? With the level of pollution and the climate crisis any industry should be worried! Also who drives of course, and here the engineering plays other time a very important role as the driving style.
For instance, the same model of bike, with 500cc of a well-known manufacturer, has been evolving to reduce the high gap between logic and reality with cars breaking limits after numbers like 3.6l/100 km have been appearing in the lists. This model of 500cc went from 5.0l to 3.5l of average so this time is better. Users of older models would be polluting much more for the same performance and at the same time spending much more money. Make a simple multiplication like 1.5l per 100 km during 100.000 kilometers and we are talking about a ton and a half of fuel and a considerable percentage of the bike's price (around 40% as of today).
It could be better though; now multiple manufacturers are starting to solve mistakes of this proportion destining more efforts in optimization. There are also regulations to come, more strict; and a more informed population that demands efficiency.