Originally Posted by
gerv
Actually the bikes of the 1970s were often heavy, clunky department store bikes. Department stores like Sears rather than Walmart... but the idea was much the same. The big difference -- I've repaired both ancient Sears bikes and recent Walmart offerings -- is that the former were pretty bullet proof. Even 30-40 years later, some of the parts are still working. Light they weren't, but they were durable.
Remember, however, that the 30-40 year-old bikes you're seeing are the survivors. The ones that were crap are long gone.