‘a growing number of psychologists say that this mountain of evidence is actually a house of cards, built upon flimsy foundations. According to Kenneth Paap, a psychologist at San Francisco State University and the most prominent of the critics, bilingual advantages in executive function “either do not exist or are restricted to very specific and undetermined circumstances.”’
peakmemory 
This kerfuffle reminds me of John Ioannadis’s influential meta-paper “why most published research findings are false” [http://robotics.cs.tamu.edu/RSS2015NegativeResults/pmed.0020124.pdf]
The Ioannadis paper has had a big effect in psychology, where we are still wresting with the “replication crisis”
https://en.wikipedia.org/wiki/Replication_crisis#Replication_rates_in_psychology
It s certainly not a very plausible proposition. Why should the fact of something not happening demonstrate the existence of some other things stopping it from happening?