In a perfect world,
the onus would be on Jo Boaler to prove her theories... rather than use our classrooms full of children as lab rats for her experimentation. Unfortunately (and un-scientifically) Jo Boaler does not appear to provide sources for her theories/claims.
Be that as it may, the following barely begins to scratch the surface, but might help a bit?
1)
Serving Students with Exceptional Promise March 9, 2018
STEM Network Working group
... a video by Jo Boaler has caused some to question the importance of identifying gifted students. This is a response from the NAGC STEM Network Working Group.
2)
Research That Supports the Need for and Benefits of Gifted EducationSally M. Reis
March 2, 2008
12-page PDF file, linked from the aforementioned article on the NAGC website.