Einstein was a theoretical physicist. Without his theories:
* Japan might not have been defeated in WWII.
* There might be more coal power plants, because there would be no nuclear power plants.
* GPS probably would never have worked.
* We'd have fewer successful space missions.
* There would be no superconductive magnets.
* There would be no digital cameras or solar cells.
* There would be no lasers.
I could keep going if you want...
References:
https://en.wikipedia.org/wiki/Albert_Einstein
https://en.wikipedia.org/wiki/Theory_of_relativity
http://www.guidetothecosmos.com/present_wwe.html