The idea that the Covenant with the Jews is over is all but explicitly expressed in the Epistle to the Hebrews.
In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away.
... yeah, literally in the same set of verses:
10 This is the covenant I will establish with the people of Israel
after that time, declares the Lord.
I will put my laws in their minds
and write them on their hearts.
I will be their God,
and they will be my people.
11 No longer will they teach their neighbor,
or say to one another, ‘Know the Lord,’
because they will all know me,
from the least of them to the greatest.
12 For I will forgive their wickedness
and will remember their sins no more.”
I guess by "all but explicitly" you mean "explicitly not"...
That sounds pretty specifically like they're still the chosen people of YWHW. Further, it's not because of a group of them's giving up of Streaker J to the romans that the old covenant has waned -- it's just because there's a better priest in town.
Hebrew 6 also kiiiinda' mentions YWHW's inability to lie, which I'd say would preclude its breaking of old oaths. The covenant may have changed, but promises previously made would likely still hold.
Also as noted, the whole "subset of wicked Jews doing wicked things and then better ones coming along" is apparently a very standard judaic literary technique, at least during the periods the torah (and related texts) was being passed along and eventually transcribed. Sort of an applied No True Scotsman thing. It... probably doesn't actually mean that much, from the text's perspective.
No lost claim sighted?