And this is your opinion.
The difference is that you have no first hand experience of selection, undergraduate and postgraduate medical training, or the practice of medicine. Instead, as a self-described parent of a junior doctor and a secondary school science teacher with a medical career advisory remit, you have personal biases that I can only assume explain your lack of engagement with anything that resembles evidence and your overestimation of your competence in this field.
I explained how and why academic attainment was deprioritised. A committee formed of the heads of recruitment and admissions from a consortium of medical schools met at a northern university somewhere between 2000-2005 to develop a standardised points-based admission system, which had the specific aim of making doctors more like the patients that they serve. (In a related publication it was noted that "there is little substantive evidence that the medical profession as a whole will benefit as a result of this increased diversity in its workforce".)
A historic workforce of "arrogant doctors who didn't seem able to communicate with patients or staff" is a construct of your imagination. Although ironically it has become a problem, with graduates of PBL and post-2000 medical schools overestimating their abilities and disproportionately attracting the attentions of the GMC.
Far from not being "bothered to train" junior doctors, senior doctors are overwhelmed by the time that they spend on them, and also voted last year in overwhelming numbers to halt the roll out of PAs.
I don't even know where to start with "being book smart is only one measure of intelligence". Suffice it to say in this context that being book smart is the best predictor of progression in medicine.
As for Van-Tam, his A-levels were as good as, or better than, 45% of contemporary male entrants to medicine. He entered on the strength of attainment, nothing to do with his father's occupation - unless of course Wikipedia is correct and his father was in fact a maths teacher in Van-Tam's grammar school, because who knows, perhaps he was a careers advisor too.