Can oxides build up enough to force contacts to disconnect?
There's no question that pins can oxidize and that the build-up, perhaps combined with minor movements, can lead to an eventual increase in resistance, leading to possible additional heating at the connector, leading to more oxidation, etc. I've seen it happen, on occasion. Faster, when the humidity is high.
If the alloy or metals are dissimilar, in the sense that their anodic indices are different, there will always be a galvanic potential present. In the presence of an electrolyte (tiny amounts of water from the air, for example), this potential can drive ions as well as provide energy for chemical changes.
Each metal is a special case, though. So there is no specific "bright line" that will tell you exactly what happens in every circumstance. Aluminum, for example, oxidizes into what amounts to "transparent aluminum" or sapphire. Abrade any piece of aluminum in the presence of oxygen in air and it will almost immediately form a thin layer on its surface. Given enough time to act, it grows thicker and thicker and it can become strong enough to resist scratching to a degree as well as to insulate. Iron, on the other hand, develops a very soft iron-oxide with entirely different characteristics. (Not that pure iron is ever used in circuit connectors!)
So... It's possible. I've seen it happen with instruments kept untouched in a remotely located electronic shack where it was no more than re-seating of a board or two (to remove some of the accumulation) to get things back running.