Vacbear, I too thought that it made for an interesting read, indeed I'd like to know more and based on her last reply I am sure I'd get another. However, I don't want to put her to that bother!
Like you, I was also intrigued at the comments about the cleaning looking old in 1974. So, with little else better to do, I sat and pondered the point. By my calculations, this woman must have been in her early 20's when she got married, if she has only just retired. Now, I realise I can speak only for myself at that age (I can just about remember it) and I will readily say my perception of many things then was not what it is now. What was "old" to me then might actually have only have been a few years in age. To be given a brand-new cleaner which was already four or more years old may have felt like 10 years to a young bride!
I then also considered the 'loaf' shape of the cleaner, with its rounded top and silver glides underneath. By 1974 a lot of cylinder cleaners were of course much more square and rigid in their styling, and above all, a lot were mounted on wheels. They also didn't have the levers on the side to clamp the front cover in place; I'm thinking along the lines of the Electrolux 330 and 94 here, the Hoover Freedom, and the vast array of imported cleaners which were largely constructed of plastic and had a bag with went in through the top or middle, such as Meile and Philips. So in that respect, I can possibly see why it may have been seen as dated. Clearly though, at least I think so anyway, it is apparent that the woman was very appreciative to have a vacuum cleaner at all, and of course it was also brand-new into the bargain.
What amazes me is that from her message it sounds like the Trident certainly earned its keep, and whilst the tools had all been killed-off, the hose remained in tact. In my experience they were the first thing which people wore out.