Oh yes
That has a lot to do with this being his breakthrough season imo. The media/fans love a shiny new toy. Martial was considered Ballon D or material last year, now Mbappe is considered the bigger talent.
Ousmane Dembélé was the emerging star last season in France with Rennes. He preferred to join Dortmund instead of clubs like Barcelona. And he is successful there.
Who considered Martial as Ballon D'or material? Certainly not the French medias/followers.
Also Martial plays for big, bad Man United - one of the most hated clubs. All the fanboys out there love players from Dortmund, Monaco, Atletico etc. As you rightly said, the shiny new toy thing plays a part also. If Mbappé signs for a big club, many will start the 'overrated' rants due to hate. Viscous circle.
Hate is the price to pay when you're powerful: the same applies to clubs like PSG in France (most of French people were happy to see them kicked out by Barcelona btw) and probably Chelsea/City.
Why is the Martial acquisition overpaid? Because of the medias and 'fanboys'?
The explanation is sample: the wealthiest club in the world needs a big name/potential few days before the end of the mercato period ---> you necessarily overpay due to the bad timing
I'd agree with this. Let's wait and see Mbappé do it in a proper league, which I hope he does.
The right question is: is France a proper producer of talented footballers?
People seem to be ignoring the fact that Martial has gone backwards this year.
The comparison Mbappé-Martial is very interesting because they played with the same players for the same club under the same coach in the same era.
M'Bappé ---- picture at the age of 17 years
Martial ---- picture at the age of 18 years
If you watch him nowadays, M'bappé looks physically stronger than Martial and it's a key factor of success in the UK. Martial is more versatile.
Intentionally stupid?
The French league is a weak league, this is backed up by the UEFA coefficient. Is that stupid too?
Did I say good players can't come from the French league? No.
If a club acquires Mbappe, it means:
a) the club acquires the French league? No
b) the club acquires a player coming from a League with a proven track record in terms of production of talented players successful in the EPL? Yes
Newcastle is known in France for being a club that overpays average/decent players. M'bappé is another story: already an elite player in a French context -> How many players have scored in the French League more goals than him at the same age? I don't see, I will research another day.