Half of people with Alzheimer's carry at least one APOE ε4 allele. However, a full quarter of the population carries that mutation, and most carriers never go on to develop Alzheimer's. Lifestyle matters a lot here.

This kind of misdirection is not helpful for educating people on changes they can make now to reduce their risk, rather than waiting for a silver bullet. Alzheimer's research is well-funded in the US as the octogenarians running our congress are personally invested in it.

My understanding is that there are forms of dementia more tied to genetics than "Alzheimer's". One that has links to genetics is Frontal temporal Dementia.

To the extent that lifestyle helps, which is not zero, you need to exercise. "Become a cabbie" is NOT an intervention that is going to help whatsoever.