You are saying "Everyone", no it is not everyone. That is definitely not the case for my employer, Google. For Google and many other top tech companies, you can negotiate for higher salaries or bonuses and use your previous experience (or other things, like competing offers) as leverage. A new hire can be have a higher compensation than you (assuming hired at the same level), even if you have been at the company for several years. Or, of course, you can choose not to negotiate. The point is, it is not "everyone" that starts off at the bottom of the ladder. It would be pretty asinine if the norm was to have some 10 YOE engineer starts as entry level and has to work his way up to senior level upon getting hired at the company.
If this is a foreign concept for the company you work for, then you work for a shitty company (even if they make awesome products). It is a completely different issue.