Most record deals are set up so that the label owns the sound recording copyrights (i.e., masters) forever. This business was built on catalogs - Capitol and RCA would probably not be around today if they did not own the masters to the Beatles and Elvis. Hence, labels do not part with masters easily. However, it’s possible to get a reversion of the masters at some point, but the artist would have to ask the label for this concession to be built into the contract. Normally, a reversion might kick in if: (1) the label fails to commercially release the masters, or (2) a certain amount of time goes by (e.g., 10 years) where the label had time to squeeze all the profits out of the masters (which normally have a life cycle of no more than 5 years unless it’s a big hit). There is also some language built into the Copyright Act that copyrights can revert after 35 years, but that involves some hoops to jump through and no one wants to wait until they are an old fart to get their property back so try to built it into the deal as discussed above.
Ben McLane Esq