I have worked for more than 6 years now and have worked for multiple different projects under various fields for 3D for example, Product visualization, Character Animation, Movies, TV Commercials, Car Commercials, Architectural Visualizations. I would say out of them all the most saturated is the Movies and Architectural Visualization fields... There are just too many people doing the same thing, so there is very few clients out there that require quality work done.
But if you love what you do then this doesn't bother you, bcos do what you love and keep on it. There are only a few people who really enjoy the work they do and have taken the time and effort to make it to the top. Once you struggle your way out of the conventional pool of monotonous work, you will see there is an amazing amount of potential out there.
I have been working for a Architectural Contracting company abroad for 2 years, I wouldn't say experience doesn't really get you into these companies, work counts like if you have done visualization for a project that they are currently working on then it is more likely that you will get hired and also obviously luck based. For example a huge company like I worked for usually sends a manager and an HR personnel to take interviews to a dedicated Recruiting Agencies. So if you happen to be at the recruiting agency when the interviews are taking place and you have work that is related to the projects they are looking for they will hire you.