The short answer is no.
Many jobs are still not advertised online or in the paper.
Some jobs are filled internally by employees within a company being the first to know about a job opening within their department or another department in the company.
Some employers and hiring managers may be interested in hiring someone, but for several reasons, they may decide not to advertise. Their preference may be to head-hunt/search for potential candidates that match with the skills and experience they are specifically after, rather than advertise and have people applying who may not be suitable.
Picking up the phone and calling a prospective employer to briefly introduce yourself to find out if your skills and experience would be of benefit to their company and of course if there is a potential job availability, can be a great way to get your foot in the door and tap in to the hidden job market.
Client Centric Executive Employment Solutions is an Australian based business that assists with CV/Resume writing, addressing key selection criteria and covering letters to help you with give your best foot forward to an employer. Please feel free to visit their website: www.clientcentric.com.au