Do you mean steam engines or internal combustion? Steam engines had been in use for the better part of a century before the internal combustion engine was developed. Steam power spurred the industrial revolution and forever changed the world. When internal combustion was invented it was usually seen as a further development of industry and in certain, typically smaller, applications quickly superceded the steam engine. Its compactness and power helped get the automobile and the airplane off the ground, so to speak. The emissions were considerably better than the amount of soot steam engines produced.