Uff thanks for the link, and yes, "less advanced" is definitively a clumsy wording to make his point.
I think basically the same point was made about the PSG, explaining their chokes in Champion's league because they don't have enough high level rival in the french ligue1 so are less used to support the higher pressure during knock-out phase of the CL.
Just like Argentina and Brasil it doesn't stop them to reach semi-finals or more as they don't lack talent, but it is still an additional drag they have to overcome to win the competition.
All in all it seems to me quite trivial to get tripped on, but it is easier for me as I'm not south american !
It didn't bother me nearly as much as some others, but I found it quite inaccurate and indicative that Mbappé perhaps doesn't know much about international football outside of Europe. It is accurate to say that the leagues are far less competitive, but it isn't so much to say that the national teams are. The leagues are not at European level because they can't economically compete with Europe for players (with a dash of corruption issues), but the clubs are basically irrelevant to the national teams. Very few Brazilian and Argentine national team players play outside of Europe, Mappé plays alongside the two most famous South American players as we all know. So the lower level of competition at the club level is largely irrelevant to the World Cup.
Mbappé was, of course, referring to the national teams, and that's where I think he made a mistake, perhaps born out of not watching enough South American (CONMEBOL) international football. It is true that there are fewer "top" national teams in South America than in Europe but there are also teams in Europe far far worse than the worst South American team (Venezuela, generally). In the final qualification stage France had to play Finland, Ukraine, Bosnia & Herzegovina, and Kazakhstan. Finland (or perhaps Ukraine) was the toughest opponent France faced in qualification. Finland/Ukraine are probably better than two, maybe three, CONMEBOL teams at most. To qualify, Brazil and Argentina had to play everyone else in CONMEBOL twice, including each other. That's at least 6-7 opponents more difficult than France's most difficult opponent.
The other aspect Mbappé and many Europeans seemingly aren't aware of are how challenging the road environments are. The travel is immense, South America is many times larger than Europe and the physical challenges can be staggering. European teams largely face each other in temperate conditions at near sea level. During qualification South American teams will often play in a huge variety of climates and altitudes. Bolivia is considered a "weak team" but defeating them in La Paz is enormously difficult. The stadium, for example, is at 3,580m above sea level. Playing at that altitude is insane. I've been to La Paz several times and get a head-ache just walking around. In other countries you can expect games at 40c with near 100% humidity, etc. That's why the comment comes across to me as mistaken, though it did not offend me like some others.
Argentines and Brazilians were bothered although the other South American countries were offended more for the most part. Mainly because it seems to imply that they are "weak". Trust me, every team in South America would beat teams like Kazakhstan and Bosnia and Herzegovina. Mbappé wasn't the only one to say something like this, many European pundits said the same as did other players. Thomas Meunier, for example, said that winning the Euros was better than winning the World Cup since "except Brazil, all of the best teams are [in Europe]". He said that before Belgium lost to the African nation of Morocco, of course.
Anyway, I think we can all leave this in the past now, certainly is silly to continue to get stirred up about (although I would enjoy the cup remaining in the American continent next cup as well, particularly of Argentina can win it again jaja).