why didn't the people disown
Feanor sons to get themselves out from under that curse?
That may not have been such an easy thing to do...
I have a long ways to go on this, but I'm following this chain of thought at the moment:
"The lust of
Melkor and the arrogance of
Fëanor (expressed in his Oath and the revolt of the
Noldor) tainted the jewels, so that thereafter all desire for them came to an
evil end."
Notable too is: "The torment, destruction, and loss of integrity foretold by
Mandos for the Exiles, especially the
House of Fëanor, and those (the
Sindar and the
Edain) who became involved in their futile attempt to recover
the Silmarils. The curse was provoked by the disobedience of the Noldor to the will of the
Valar and by the Kinslaying, which defiled
Aman. By this Doom the
sons of Fëanor became treacherous, deceitful, and overbearing; the burning of the
ships at Losgar, the distrust of
Thingol for the House of Fëanor, and the deaths of
Finrod and Dior showed the effect of this stain on the
spirits of the Noldor."
So it seems as though the Silmarils, corrupted, contained a certain power of their own - (much like the '
one ring' perhaps, working its will in a way to return to its master) - and "buying into" the refusal to give the Silmarils over to restore the destroyed
Trees etc. was a terrible disobedience and rejection of the will of the Valar. As was participating in the kinslaying on behalf of the Silmarils etc.
So indeed, like Melkor who multiple times refused repentance though offered, and
Sauron (though we know less about whether he was offered opportunity but no doubt it was always there), those Noldor who did not repent of their rejection of the Valar remained under the "doom" foretold for them by Mandos.
Primarily,
@Aldarion hits the nail with his head as usual. I'll re-word this way:
The CHOICE was always there for them to repent. Some indeed took it and received the just reward. (Release from the Doom.)
But perhaps the 'working' of the Silmarils, and certainly their own pride and decisions in "who they would follow", was what sealed their fate.
Bottom line: "Why didn't they just break their oaths?"
CHOICE. Some did. Most didn't.
It's an intriguing question I'll continue to probe for some time.