1 million books were printed last year in America alone, and another 2 million were ebooks. The chances of any of us wannabe fiction authors are a million to one.
Maybe, but you can shorten the odds. It is true that sending a manuscript even to an agent let alone a publisher without doing anything to pave the way will most likely send it no further than the slush pile.
There are workshops not just in writing but also in editing (your manuscript needs to be publishable not just promising), and in publishing (what publishers and agents want, how to write a synopsis and present the work, how to identify your market etc) and in marketing and publicity (these are 2 very different things and you will need to do both as a newbie, the promo budget is likely to be slender at best).
A manuscript is more likely to be read by a publisher or agent if it comes with a recommendation ... Be prepared to pay (several hundred dollars, depending on the length) an editor, author, or manuscript assessment agency to read it.
Publish other work along the way ... Journalism, literary journals, blogs etc ... Develop a profile as a writer.