Why didn't the ancients wear short sleeves in the summer?
Because the ancients were stupid.
If the ancients had been so stupid, would we still have a Chinese heritage today?
This is the first time I've seen a Chinese person wearing short sleeves.
These are called half-arms, and they are worn on public occasions. The long sleeves are very thin, and they serve as the equivalent of today's sun shades.
What about private occasions? Who cares what you wear then.
This kind of thing, to put it bluntly, is just a layer of tulle on the inside and the outside.
Well after all, it is a married woman, wear in broad daylight or to wear ha.
The Song and Ming Dynasties were much more conservative - but not so much in terms of conservatism as in terms of warmth. The climate in the Song and Ming dynasties has been getting colder and colder, and by the end of the Ming Dynasty it had completely turned into a "Little Ice Age". It's silly to wear short sleeves on a cold day!
If there is a relationship between warmth and conservatism, it must be that the need for warmth leads to (seemingly) conservatism, not that conservatism is the reason why they are designed to be worn in such a way as to make people die of heat.