The environment for watching stars at night has changed.
Compared with watching the stars in the dark yard in the past, people now see that the surrounding environment of the stars is bright, whether in rural areas or cities. With the popularity of lighting, when night falls, the lights on the ground are brighter than the moon and stars in the sky. This contrast will naturally reduce the visibility of the stars in the night sky, so in our eyes, there seem to be fewer stars in the sky than before.
Now, people want to see as many stars at night as they did when they were young. They can go to remote villages or camp in the open suburbs. In that environment, friends will find that there are as many stars far away from the lights in the dead of night as when they were young.
There is also a saying that this is related to our current air pollution. Due to various toxic and harmful gases emitted by industrial waste gas, automobile exhaust gas and domestic life, the content of particulate matter in the atmosphere is increased, thus reducing the visibility of the atmosphere and the stars in the sky.
The above answers are for reference only.