Trade can reduce redundancy, that's true. With higher trade barriers between localities, you have one dominant player per locality. With seamless global trade, one player can dominate the entire global market.

However, trade also increases output, and with it, the diversity of goods/services.

60 years ago, television media was dominated by three networks. Today, there are dozens of cable networks, and millions of creators who broadcast through video sharing sites like Youtube. So there are many more sources of video-based media, and that is owing to greater economic sophistication brought about in large part by efficiency gains through greater commercial-exchange/specialization.