I think it is a bit of a cyclical thing, hee hee, momentum keeps it going for a while, then it naturally slows down. I like vintage, classic looking frame sets, but I like them with modern components. I think that is likely true for for many riders that are a generation or two after me. I'll take comfort and performance over nostalgia, any day. But, I am not a collector, I have bikes to ride them.
As for steel feeling sluggish, that is too general of a statement, IMO.