Prduct managers are at a very senior level as they are the ones who make critical product based decisions which directly affects the organizations business. There are two ways for a company to believe in you - one, get an MBA from one of the tommost b-school or gain a lot of experience
To get expereince you'll have to start off very small and the growth process here is very slow.
Its always better to get an MBA, as your growth is quicker and these B-schools train you with the required skills which companies hiring you can rely on.