As others have stated up thread, small communities do not have the tax base to afford fulltime paid first responders. Also there are some volunteer fire/ems departments that are closing or limiting services because the taxpayers in their districts are voting down tax increases or tax renewals. Of course that is the right, privilege, and prerogative of the citizens, but you get the services you pay for.
Fire departments are slightly different because they were originally established to protect the public, not a collection of individuals or businesses. Fire departments were set up in cities at a time when the possibility of a fire in one building spreading to surrounding buildings -- and potentially even engulfing entire neighborhoods -- was a real threat. When the fire department responds to a fire at your home, one of its primary purposes is to protect not your home, but the neighbors' homes.