Yes, but in many cases, people still expose the jars (ceramic or glass) to sunlight, for some days or weeks. I remember older relatives in my family doing that

Yes, but in many cases, people still expose the jars (ceramic or glass) to sunlight, for some days or weeks. I remember older relatives in my family doing that on house terraces as a kid. My guess is that the sunlight sterilizes the contents (sunlight in many parts of India is strong, particularly in summer, being somewhat near the equator), and may even change the flavor by some reaction. So there is a combined preservative effect from the factors you listed, plus sunlight.