Well, it depends on how far you go back in time. Even budget machines used to have more metal on them--some were even made almost entirely of metal--and had no self-destructing circuit boards. The big difference of all--and the reason many of these older machines are still around decades after they left the factory--is because they were designed to be repaired, and not just chucked into the landfill after a couple of years. In fact, manufacturers have found the only way they can kill their older products off is to make sure replacement parts are no longer available for them.
By comparison, modern plasticrap vacs are basically designed to self-destruct after a few short years. Cheap plastic parts break, circuit boards burn out and are made obsolete very rapidly, and users neglect to clean the filters. Since there's no good way to repair them, they end up in the dump, which is bad for the environment. They may be a little heavier, they may belch a little dust, but because they don't add significantly to the solid waste stream beyond the occasional filter bag, they're definitely more environmentally friendly.
Can you tell I'm just a little biased towards the older machines?
