I also once heard a vacuum cleaner salesman say (and yes, that used to be a thing) -- we know we can make vacuum cleaners less noisy (drop the universal motor IIRC), but people buy vacuum cleaners assuming the noise == power.

I have actually heard that some manufacturers purposely make their vacuums louder for this reason.

I have a Miele and it is much quieter than any other vacuum I have heard.

Imagine if a Prius or Tesla instead had as much noise/HP as a conventional vacuum cleaner.