But the "remnant" does not mean a minority who are saved. This is merely your definition of it and Paul shows us in Romans 11 that it is incorrect.
In Romans 11:7. He writes, “What then? Israel failed to obtain what it was seeking. The elect obtained it, but the rest were hardened” (or blinded). He then asks, “Have they (the non-remnant who were hardened/ blinded) stumbled so as to fall?” And his answer was: “By no means!” (11:11).
He then spoke of their full inclusion: “Now if their stumbling means riches for the world, and if their defeat means riches for the Gentiles, how much more will their full inclusion mean!” (11:12).
He explains the reason for the remnant. God blinded the eyes and hardened the hearts of the unbelieving Jews as the means by which all of Israel might be saved (Romans 11:25-26)—all of Israel including those who were blinded and hardened (the non-remnant). Though the unbelieving Jews had become in some sense “enemies of God” (11:28), they nonetheless became “disobedient in order that they too may now receive mercy” (11:31).
The remnant actually has universalist implications, the exact opposite of what you say: “For God has imprisoned all in disobedience so that he may be merciful to all” (11:32). So thanks for bringing the point up.