I don't think Revan and others are arguing anything about home advantage, or team strength or anything else. All those are just discussion points, reasoning given to the available statistic based on ALL the existing data. The basic point he is establishing is that -
Statistical fact:
"of all the 2 legged KO ties to-date (including round of 16 or not) that ended in 0-0 in the first leg, it is observed that in >60% of them the team playing home in the second leg went through"
Inference:
In the next how so many games, that % (of second leg home team going through) is not likely to change by much. which means, that, of the next 100 games that end 0-0 in the first leg, >60 of those ties will end up with the team playing home in the second leg as the winner.
Note 1: This inference is just mathematical/statistical deduction, no assumption. Now the reasoning is what lot of folks are discussing about, which may be true in parts or combinations, mostly subjective. no way to quantify that. These discussions include - home advantage, team strengths, team forms, players quality, manager luck, what not, you can say whatever. but it doesn't take away from the FACT that >60% of the time, the team playing home in the second leg ends of going through (with tie 0-0 in the first leg).
Note 2: This in no way tells anything about any single tie, is there a way to say liverpool or bayern will win with any certainty?- NO. too many other variables involved. But one thing you can say is that, historically, there is >60% chance that bayern will go through (not looking at the rosters, forms, xGs bla bla).
Note 3: This 65% win percentage might change over time, due to many factors that you and others underline - the home advantage is reducing over time, teams and tactics getting better so home advantage will take back seat eventually.. which may shift the that >60% to closer to 50%.