Such low numbers in a close race (final total was 52.6% to 47.3, Bernie lost by just 605 votes) indicate the Dem electorate is not that enthusiastic about either candidate. This would have implications in the general election.
November will be ALL ABOUT who can get more people to show up and vote. Trump has repeatedly demonstrated that his people WILL show up.
Oh there is a great amount of enthusiasm for Sanders. Nevada being a caucus state was easily manipulated by the clinton machine.