The overuse of thin fonts might look dated in the future, but I don't agree that this trend is totally inspired by retina screens. If anything, I think Serif fonts have seen the greatest resurgence on web due to Retina screens. High DPI screens will impact our perception of all fonts, just as sans serif grew in popularity on lower dpi screens causing their perception to be more modern and technological.

In general typography as a whole has become much more interesting on retina screens. So yes, fonts look better now than ever before so don't cheat by using superthin because its trendy.