First, we should note that the verb ἀπόληται is aorist subjunctive middle voice - an impossible sense to convey in English. However with some explanation, it is possible to gain some of the meaning intended.
- Middle Voice
First I note that the voice is "middle" meaning that the action of the verb is performed upon the speaker. That is, the verse is saying that those who believe in "Him", ie, God's only Son, will not destroy themselves; or at least, cause themselves to be destroyed/perish.
That is, not believing in Jesus, results in the destruction of the person. Put another way, each unbelieving person will be responsible for their own eternal perishing.
- Subjunctive mood
In Daniel Wallace's "Greek Grammar Beyond the Basics" (GGBB), page 462, we have this helpful series of remarks:
Descriptions of the subjunctive and optative moods in standard
grammars tacitly assume that the optative was still in full flower in
the koine period. But it was dying out. The reason is that it was
too subtle for people acquiring Greek as a second language to grasp
fully. ... in the NT there are 1858 subjunctives and 70 optatives - a
ratio of 27:1! This simple statistic reflects the fact that in the
Hellenistic era the subjunctive is encroaching on the use of the
optative.
All this makes our task trickier! On the same page, GGBB goes on to say,
On the other hand, sometimes the subjunctive acts like a future
indicative. The two morpho-syntactic categories are really quite
similar (and perhaps derive from the same root). in independent
clauses, for example, the subjunctive cannot be said to express
"probability."
Then on page 474 of GGBB, Wallace gives this analysis of John 3:16 -
τὸν κόσμον, ὥστε τὸν Υἱὸν τὸν μονογενῆ ἔδωκεν, ἵνα πᾶς ὁ πιστεύων εἰς
αὐτὸν μὴ ἀπόληται ἀλλ’ ἔχῃ ζωὴν αἰώνιον.
He gave his only Son, in order that everyone who believes in him
should not perish but should have eternal life
The fact that the subjunctive is all but required after ἵνα does not,
of course, argue for uncertainty as to the fate of the believer. This
fact is obvious, not from this text, but from the use of μὴ in John
10:28 and 11:26, as well as the general theological contours of the
gospel of John.
[Emphasis and bolding etc, as per original GGBB.] I agree.
From all of this, we conclude that John's use of the aorist subjunctive in John 3:16 is essentially equivalent here to a future indicative. Thus, we read Jesus' statement as one of future fact based on conditional conjunction ἵνα (hina = "so that") - if a person does not believe, then that person will be responsible for their own perishing.
APPENDIX - Eternal Fate
It is possible to see the personal responsibility of the righteous and wicked in specific prophecies of the second coming of Jesus:
The Righteous:
Isa 25:9 - It will be said on that day, “Behold, this is our God; we
have waited for him, that he might save us. This is the LORD; we have
waited for him; let us be glad and rejoice in his salvation.”
The Wicked:
Rev 6:15-17 - Then the kings of the earth, the nobles, the commanders,
the rich, the mighty, and every slave and free man hid in the caves
and among the rocks of the mountains. And they said to the mountains
and the rocks, “Fall on us and hide us from the face of the One seated
on the throne, and from the wrath of the Lamb. For the great day of
Their wrath has come, and who is able to withstand it?”
Note that the wicked request death and destruction and the righteous are filled with joy at the appearing of Jesus.
