matias,

The reason they sell is because they're at the top of list when it comes to 'sound quality' and functionality. And the price point is usually at or better than the competition. That is why they sell, period.

If Yamaha made Keyboards with 'true' full size Keys yet didn't provide what I stated above, you can be sure that most Keyboardists' would look elsewhere for their Keyboard needs.

And if other Manufacturers had the 'quality sounds' and functionality as we see in Yamaha Keyboards at a good price point, ie., "at or below the competition", and HAD Full size Keys you can bet that nearly "ALL" people shopping for a Keyboard would buy from those Manufacturers. Because they get the benefit of not only 'quality sounds' and functionality but also 'true' Full size Keys.

People are willing to put up with smaller Keys if they get a Board with quality sounds and functionality at a price that is usually below the competition. So even though Yamaha has the smaller Keys other Brands don't sell as well as Yamaha's because - though the other Brands have 'true' Full size keys they don't necessarily have the 'quality sounds' and functionality (ease of use) and at a better price point than the competition, ie., (Yamaha) does. But you can be sure that if the other Manufacturers had all the ingredients I listed AND Full size Keys they - "Keyboardists" - would unequivocally buy those Boards.

Maybe why Yamaha is able to offer Keyboards at a better price point is because they save money by making them with 'smaller' Keys? Yes, I am being sarcastic because we all know that the Keys aren't made of ivory anymore so making the Keys a little larger adds little if ANY cost to the cost of Manufacturing them.

Best regards,
Mike