-It looked less than freak imo. Appeared to lose the back end of the car, and slid backwards at quit a pace into the wall. If the circumstances to the changed even slightly, its very possible to see how they might not have walked away. To my eyes, being knocked unconscious whilst wearing a helmet is concerning
suggesting high impact forces.
I think it's just a matter of how much risk you are personally willing to accept; for several years formula one refused to address safety concerns & I think its fair to say objectively that the protections in place were very inadequate. But for the drivers - they accepted the inherent & residual risks involved - and that was their choice to make.
For those with the means, investing in £600-1000 safety equipment to keep you safe (or at least a degree safer) in the event of an accident, freak or otherwise, is a worthwhile & justifiable investment. Leaving them with a much lower residual risk ratio to accept than the next person who did not spend the same. The next person may simply not have the means, or its a choice between, spending the money on the safety equipment or not being able to pay for time on track and fuel - and accepting the risks, they opt against the safety expenditure.
Going back to the OP's question, I think it's been addressed. OEM reclining recaro's aren't optimum - there's evidence provided that they could indeed fail you in the right circumstance so the choices to make and the risks to accept or not are down for you to decide