I keep noticing that my rep on main and meta are the same. Is this true for everyone and if true why is it so? (as opposed to say stackoverflow and meta.stackoverflow)
It is true for everyone AFAICT, and it is also on other SE sites. (For example, compare me on English.SE with me on meta.English.SE, or someone on SF with the same person on meta.SF.) I'm guessing meta.SO is an exception because it's the meta site not just for SO but for the software; note that you also have a different user ID number on meta.SO than on SO, which is not true for the other sites and their meta sites.
That said, I can't answer "why is it so" (why one has the same rep on each site as on its meta site).
Your reputation on meta is "inherited" from the parent site because this meta is about the parent site. Active users (i.e. higher reputation users) need to have the increased privileges on this site when it comes to discussion issues regarding the main site.
Meta reputation work this way across the network. Meta.stackoverflow is the exception because that meta site also serves as the network-wide meta site. It's considered "completely separate" from all the other Stack Exchange sites.