What is the most popular type of bag?

Can you tell me, what is the most sought-after variety of bag in today's market? Is it a specific design, material, or perhaps a certain brand that dominates the preferences of consumers? I'm particularly interested in understanding the reasons behind its popularity and whether it's a trend that's been consistent over time or a recent development. Could you elaborate on the factors that contribute to its widespread appeal and how it differs from other types of bags?