Not one iota of that last analogy relates to this topic.
Eternal Security is scripture. Or, Jesus was a liar, as is God, and Jesus died a failure.
At this stage that is precisely what unbelievers are putting forth. They are unbelievers in the Gospel that teaches God's grace gave us irrevocable eternal salvation by God's choice, not our labors to earn it.
This fact is all through Jesus ministry. It is not diminished by unbelievers in it. It does not become less because unbelievers do not see it.
In fact, unbelievers are a blessing in that their fixation with denying sinners are washed clean forever and are grace filled and irrevocably saved so not to perish as a dead in sin sinner, prove other parts of the true words of Christ.
The natural (sinner) mind cannot understand the things of God. Because they are spiritually discerned.
Those who have the Holy Spirit and are forever saved from perishing under sins, do understand the things of God. Like eternal irrevocable salvation by grace of our Father.
We won't reach those natural minded folk. And they shall never, no matter how many threads they start, shall speak over God's truth of eternal irrevocable salvation.
It is a shame they try. However, it is also a condition afforded sin nature, natural, worldly, minds that think God needs their help and consent to keep his word. That they believe they can overcome by choice and deed at any time. Making human behavior able to overcome divine covenant.
That's sad. And shall always be error.
"OSAS" Isn't heresy. It is divine favor. Unbelievers will never see that. Unless the Holy Spirit changes their mind. Him! Not us.
And that's it.