A very interesting article and I agree with some of what you have said. Sadly, though, this looks at the concept through a very narrow lens. As a mental toughness coach and trainer I agree that the 'model' of mental toughness you outline is flawed and very myopic.
When we look at it through a peer-reviewed model generated from over 30 years of academic and practitioner-based research and development, the construct is more relevant and useful.
The UK researchers quoted are from 2012 and again take a very limited view of the construct which suggests they hadn't done much detailed research on it.
Can I suggest you read Developing Mental Toughness by Prof. Peter Clough & Doug Strycharczyk? You might find it of interest.
Thanks for writing and sharing your article.