Nikola Tesla is not extremely famous because he worked on abstract ideas in an era that valued practical, profitable results. Tesla's inventions were not incremental; they were revolutionary. While Thomas Edison sold objects that could immediately be used, Tesla's ideas were not immediately applicable, so there was no financial motivation to develop them.
One of Tesla's final contributions to the world was a tower near New York City that would have provided free wireless energy to the planet given consumption rates at the time. The investor who financed the construction of the tower shut the project down, however, when he realized he wouldn't be able to regulate the energy and therefore wouldn't be able to make money from it.
Edison, in the interest of his own profits, tried regularly to discredit Tesla's inventions as dangerous. Edison was practical and profit minded, and he was a good salesman who knew how to develop and market things that people could understand. Sir Joseph Swann invented a light bulb in Newcastle at the same time as Edison, but Edison patented and sold his. Tesla, meanwhile, relentlessly pursued seemingly impossible concepts, such as wireless energy transfer. He died penniless in a hotel in New York City.