Why are older people today are so useless?

This has become more common, and more normal, as time goes on; but it would have been considered to be uncommon and abnormal years ago.

It is all because the world's protective geomagnetic field has been gradually weakening over time.
This exposes the general population to more space-based energy and particles, mostly due to the Sun, but due to other cosmic sinks and sources, as well.

What this is doing, is it is causing space-brain dementia to develop in a greater and greater proportion of the population.
People in this condition have lost their higher reasoning ability, and are less able to learn new things. They increasingly rely on what they had learned when they were younger, and increasingly rely on their animal instincts to survive.
They have become corrupted.

Wisdom is gained through continuous learning through childhood, adolescence, adulthood, and into old age.
People who have developed space-brain dementia have lost this ability, at some point in their life.

The older a person is, the more space-based energy and particles they have been exposed to.
Also, the usual age-related degenerative brain conditions that affects some people also comes into play, and is enhanced by space-brain dementia.

But, this is not affecting just old people. Many young people are also suffering from this condition.
Currently, at least 60% of the population of younger people have space-brain dementia, and are unable to learn anything.
Keep this in mind. More than half the people that you see walking around (or driving) out there have this condition, to some extent, and they could be any age, from any walk of life, and in any level of social status or responsibility.

This will only become worse over time, because there will increasingly be greater exposure to the population; and because demented people often reproduce more prolifically than normal, rational and reasonable people do.
It will likely soon cause a catastrophic global collapse of civilization. You should be prepared for this.

I am often astounded that people in this condition quite often continue to live for a long time; and don't kill themselves, or end up getting themselves killed, because their behaviour is repetitively irrational.
When civilization collapses, most of them will likely die-off within a very short span of time (weeks to months), because they won't know what to do to meet their basic necessities of life.