What you wrote right there only prooves that what Jerome Joseph Acayan wrote is true.
If we were to say that everyone that sounds similar were ripping eachother off, we would have to complain about all the new bands and artists that have taken shape over the years.
I am sure that you could find alot of other people that make music similar to The Postal Service or Owl City.
People make the music they feel like and Im pretty sure that you will be able to compare almost every song you find out there to another one.
In the end, there is no such thing as individuality you know.