How could anyone get access to masters without going through the rights holder? No one.
However, there are also cases of bigger reissue rights deals. For example, Music Matters had a license with BN that allowed them to pull any tapes they wanted and even get them to test press stage. They paid something up front for rights and access, then the bulk on a per unit basis. Like many other licenses there was no cap on pressing quantity, so they could go back to the well as many times as possible.
Which, by the way, is what brought Classic Records down. Overpressing Led Zeppelin substantially but under-reporting pressing quantities very substantially. You don't mess with the Zep management.
The terms of any deal are largely dependent on volume. A low pressing run gets a higher license fee to compensate for the lower per copy points. Remember, the label makes money from every pressing sold regardless - royalties. A very high press run is different.
People often assume the licensing cost is the big part, but it isn't. Insurance for master tapes is. You can probably cut a deal for Zep masters, but no one outside a major could afford the insurance, and the mastering studio won't have enough insurance to cover the value of a Zep master tape.
That's why more and more, the indie reissue labels are doing B or even C titles. Not licensing. insurance.
