No he was not well past his peak. He made a 200 in one of the match. You have to understand Kohli was not exactly a ODI legend right of the bat. He came way down the order. It took a while for him to become one. Tendulkar was a veteran. Infact Kohli was part of the match where Tendulkar scored first ever 200 in a ODI. In that match Kohli did not even bat. Dinesh Karthik, Yusuf pathan, Dhoni all batted ahead of Kohli. Hobart ODI was the turning point of his career where India had to win in 38 overs or so to get qualified. He ripped Malinga to shreds. Kohli was exactly the same batsman in 2008 under-19 world cup. All the shots he plays now were part of his repertoire even then.
Kohli's game is not pitch dependent or rules dependent. He is largely a ground stroke player. That is why he scored so many 100s. His kind of game works in any era. He never sweeps. He doesn't play funky shots. Almost all his shots are text book shots. That is one of the reason why Kohli was incredibly consistent in T20 too.
Attitude has changed these days. Those days batsmen would go after bowling in the first 15 and then the last 10. Nowadays they start acceleration around 30th over.Game has evolved. Bowlers have evolved. Batsmen have evolved. Approach has evolved.
So it is hard to compare across the era. You just have to check how good he is in his era compared to others. Now we project Smith as an ATG test batsman under the same criteria. Starting his career as a tailender is averaging 61 in Tests. Labuschagne with a first class record of 35 is averaging over 50 in Tests. Should we trivialize their record? In every era you have flat pitches, turning pitches, bouncy pitches. In every era you have trundlers (probably a lot more trundlers in the bygone eras). In every era you have weak oppositions. In every era you have bad captains, good captains. In every era one team or the other go through transition. So let us just enjoy what they do in their era and leave it at that.
What do Test stats have to do with the point of ODI law changes with respect to fielding positions?
SRT was not past his peak? Twilight means towards the end of a career. (You also mention SRT was in his twilight in the overlap period). That 200 was an anomaly during the phase of his career, and don't forget how long it took SRT to score his 100th 100 from when he was on 99 centuries. SRT was well past his peak towards the end of his ODI career.
So Kohli started well down the order? So what? He still scored his 1st ODI century quicket than SRT. SRT took 70 odd ODI innings before he scored his first ever ODI century (well before power plays were introduced), which is shocking considering what he was achieving in Tests, but also understandable given the lack of fielding restrictions in pre power play era in ODI.
The fact is since the introduction of power play, it has been easier for batsmen to score runs, and this is further evidenced by the fact of 300+ scores started becoming the norm in ODI since the intro of PP, not to mention double tons in ODI - batsmen are willing to take more risks during the PP phase due to fielding restrictions.
You can call this trivialising records, but it's not, it's call adding context and perspective - you do it all the time - with scores against minnows vs heavyweight - why trivialise when a ton is a ton, right?
No one here is dissing Kohli's achievements, but no one here can tell me with a straight face that PPs have not made a difference especially considering ICC introduced the PP to promote high scoring games in ODI.
And no, we cannot dismiss good captains or bad captains across eras, captaincy is about understanding the game/situation and is a reflection of intellect. It honestly sounds like you are making excuses which I doubt you would have made if Dhoni was being debated.
If you do not think law changes in ODIs effect the outcome of a performance then good for you, because you do not have to take my word for it, you just have to listen to players of the past who say the same thing - ODI law changes, PP, and 2 balls, have indeed made it easier for batsmen to score runs.
Let me be clear, I consider Kohli an ATG, but I do not see him as a GOAT. GOATs do not need stats to justify their status. When fans talk about Warne, no one mentions his economy rate, they just remember his great performances - just as with SRT, Viv, and of course, Ponting.