Yes Paul used this physical example to give a spiritual one. It doesn't necessarily imply all those who died physically in the wilderness will not inherit eternal life. eg. Moses.
Moses wasn't one of those who were disobedient in the wilderness. Here is Paul's argument.
5 And Moses indeed was faithful in all His house as a servant, for a testimony of those things which would be spoken afterward,
6 but Christ as a Son over His own house, whose house we are if we hold fast the confidence and the rejoicing of the hope firm to the end1.
7 Therefore, as the Holy Spirit says: "Today, if you will hear His voice,
8 Do not harden your hearts as in the rebellion, In the day of trial in the wilderness,
9 Where your fathers tested Me, tried Me, And saw My works forty years.
10 Therefore I was angry with that generation, And said,`They always go astray in their heart, And they have not known My ways.'
11 So I swore in My wrath,`They shall not enter My rest1.'"
12 Beware, brethren, lest there be in any of you an evil heart of unbelief in departing from the living God;
13 but exhort one another daily, while it is called "Today," lest any of you be hardened through the deceitfulness of sin.
14 For we have become partakers of Christ if we hold the beginning of our confidence steadfast to the end,
15 while it is said: "Today, if you will hear His voice, Do not harden your hearts as in the rebellion1."
16 For who, having heard, rebelled? Indeed, was it not all who came out of Egypt, led by Moses?
17 Now with whom was He angry forty years? Was it not with those who sinned, whose corpses fell in the wilderness?
18 And to whom did He swear that they would not enter His rest, but to those who did not obey?
19 So we see that they could not enter in because of unbelief.
NKJ Hebrews 4:1 Therefore,
since a promise remains of entering His rest, let us fear lest any of you seem to have come short of it.
2 For indeed the gospel was preached to us as well as to them; but the word which they heard did not profit them1, not being mixed with faith in those who heard it.
3 For
we who have believed do enter that rest, as He has said: "So I swore in My wrath,`They shall not enter My rest,'" although the works were finished from the foundation of the world.
4 For He has spoken in a certain place of the seventh day in this way: "And God rested on the seventh day from all His works";
5 and again in this place: "They shall not enter My rest1."
6 Since
therefore it remains that some must enter it, and those to whom it was first preached did not enter because of disobedience,
7 again He designates a certain day, saying in David, "Today," after such a long time, as it has been said: "Today, if you will hear His voice, Do not harden your hearts1."
8 For if Joshua had given them rest, then He would not afterward have spoken of another day.
9 There remains therefore a rest for the people of God.
10 For he who has entered His rest has himself also ceased from his works as God did from His.
11
Let us therefore be diligent to enter that rest, lest anyone fall according to the same example of disobedience. (Heb 3:5-4:11 NKJ)
Paul argues that there remains a rest for the people of God and that some must enter into. He said we who believe do enter that rest. This is a rest in the future and Paul says that those in the wilderness did not enter into that rest. This cannot be speaking of the Jews going into the promised land as Paul has put it in the future yet at the same time says that those in the wilderness did not enter into it because of unbelief. Then he admonishes his readers to make sure that they don't miss entering it because of the same disobedience.
I think Augustine's idea of perseverance of the Saints is real interesting and shouldn't be used as support of OSAS. ( OSAS is a poor term and doctrine imo ) He has deeper inferences which suggest a believer may leave the faith but I'm a bit unclear whether he considers such a person one of the Elect. I think he suggests there are specific individuals who were chosen for specific purpose eg. Abraham, Mary etc among the saved and also people who have been called according to the election of Grace. Either way he suggests salvation is monergistic.
One of the problems with Augustine's idea is that one cannot know if they are one of the elect until death.