I have a collection of equipment from many eras. I have the latest wizardry all the way back to units now over 60 years old. So I think I am qualified to make a judgement.
First I think a lot of this is driven by nostalgia, as people want what their father's had. It is also driven by a branch of audiophoolery that says this vintage equipment is superior. In general that is not true. The prices some of these units fetch make no sense to me at all.
Your Sansui unit is respectable but not in my view superior to modern equipment. The Kenwood unit, was a fairly low end to mid end unit, of low power and not compatible with four ohm speakers according to the instructions. I would not give that unit house room.
The Hafler is an early Mosfet amp. Speaker protection is via fuses. Fast blow will blow all the time, and slow blow will not blow before your speakers are fried. So that unit is not worth giving house room to.
So what are valid issues. One is obviously playing and or archiving legacy media. The other is keeping the best of the equipment from our past in good running condition, as a type of a museum if you will, to show what really could be achieved in times now quite long ago. In my view there is only point in preserving the best and most perfectly engineered from the past.
My interest is both of the latter.
Here is a Garrard 301, which were made from 1954 to 1965 by the Queen's jewelers. They are superbly engineered. The pickup dates from 1971, and the 78 head from 1965.
The Quad tube preamp I bought in 1965.
It also plays 78 RPM shellac discs. The Quad preamp has all the different equalizations for pretty much every 78 RPM label.
Here is a picture of some of my equipment from multiple eras.
The two larger machines I bought in 1973. All the reel machines are Swiss Studer/Revox machines, except the one in the third 19" rack. This is a very, very rare British machine, a Brennel MK6 with parabolic tape path. Very few were made and most for the BBC.
The three Revox A77 machines are all restorations that I undertook.
Restoring vintage gear is truly a labor of love and takes hours and hours. Parts are a real treasure hunt, and you have to build up a sizeable war chest of parts.
Finding parts is a world wide hunt.
Of late I have been sourcing parts from France, Germany and Belgium. Today I went to use my 1980 TEAC master cassette deck, to find one of he belts have turned to glue. I managed to source a couple from Portugal. The machine will require significant dismantling since it is a Far Eastern machine.
Vintage European equipment tends to be by far the best and as a rule far more intelligently designed and laid out. This makes it easier to work on and restore.
Japanese reel to reel machines seem to be popular and get a lot of press. In my view none of them were excellent and universally thrown together and a nightmare to work on.
Here are the indards, of my Revox A77 MKIV. I had to go back into it because it blew a motor starting cap. It is beautifully laid out.
Back in action again.
You can just see a part of very rare dbx II and Dolby B encode/decode units.
Basically you need to have an object in view and not swallow BS if you are going to go vintage. If you do, go for the very best and not the junk. As is the case today, junk is prolific, excellence rare.
I think since restorers are now so hard to find, you should have service skills if you are going to get into it, or preserve your own equipment from the past.
Visitors tend to be absolutely enthralled by it, and astounded how this best of the past equipment really stands the comparison of the very best of today.
However be advised, there is work involved. You need a good reason and the interest to go down that road.