They'll get better with time and R&D, think about this: Mazda is the only car manufacturer that has actually made the engine work from a mass production standpoint so therefore any research in relation to successfully putting it into consumer passenger vehicles has been essentially done by one car company. Nearly 100 years behind the start of standard piston engine research for industrial purposes, compound that time for research with the sheer volume of companies investing time and research into them then and now and where the rotary is now is an impressive feat.
The are still quite a few companies making them in Russia, Australia, Japan and the Czech republic, its just Mazda is the only car company, they are still used in aviation although not as widely as 50 years ago and also used in model aeroplanes (German companies makes mini ones).