Generally no one was wearing dresses with 50s look after the 50s because people wanted to dress in newest styles. It's not like you could go into a store (minus thrift stores) in the 1980s and buy clothes from every era. But now with online stores you can buy from any era (new clothes in that style). Because the demand is very high and you have retro hobbyists wanting to wear retro looks, it is a new thing. You can hardly say there were that many retro hobbyists in the 50s wearing Victorian clothing. It wasn't a thing. But because now there is market for people who want to wear retro clothing, thanks to e-commerce, more demand and increased manufacturing potential, it is a relatively more modern phenomenon.