All here have replied well. Please remember that one should look at single sentences within the context of the paragraph they are pulled from; or chapter in this case. the commentaries furnished at http://www.biblestudytools.com/kjv/philippians/4-11.html
are also excellent sources for answering your question. To me, Paul LEARNED to be content with whatever he had in this physical world, for his focus was on life after death with Jesus, when this world and its items would be left behind. When one has the gift of salvation, whatelse really matters in the end.
Seems like not much would get accomplished if we all sat back in contentment in whatever state we were in.