Definitely not inevitable, but likely.
I believe the environment plays a role (moisture and road salt).
A PPI is a must for this issue.
The good news is that these engines are being rebuilt (either for bad studs or not) and the studs are being replaced with steel. The broken studs will therefore be a thing of the past in 20 years from now. ;)

G

Mine looked perfect (no corrosion southern car) at the 190K rebuild so I left em. Cross my fingers till I get to the 350k rebuild.

Ah, how the world goes round and round. It was once that steel is bad and we all must go Dilavar. It is now Dilavar is junk and we must all switch back to steel. We must all find that original Mechanical Engineer who made that first fateful mistake of specifying a steel stud for a magnesium engine case with very different thermal expansion rates, and fire him. It all goes down hill from there.

On my '87, the PO had done a top end rebuild at 64k and did not replace the studs, now I'm at 85k and have three broken on the exhaust side that I will be replacing with steel. I wish I knew more about what the shop saw when they did the rebuild and why they didn't elect to change them out as a preventative measure then!

Because you would have to change all lower studs, 12 of them, and that is an additional 4 hours, plus the steel studs at $30 a piece (the shop is not going to install used ones). and that is a cool $750. Given that everyone is on a budget, the previous owner when faced with that bill said no, I dont need it yet.