Is there any merit in former SOTA gear,

Yes, Sota was a brand of very good turntables, the acronym S.O.T.A. is for state of the art.....kind of like International Business Machines....IBM

y Garrard 301/Fidelity research arm/ hot-rodded denon 103Will hold its' value or appreciate

As I sit here listening to my Sota table...YES THERE IS MERIT.
My Sota is amazing.  However, keep in mind that most old Sota tables have speed problems.  You will end up investing in either a motor replacement or a speed control upgrade.  These can get pricey.  Aside from shipping, the upgrades will run anywhere from $500 to $2000.  Still a lot cheaper than a new table.

Old cars are nice to look at, fun to drive occasionally, but if you are going to compete at the track, you are going to go new, and that new "daily driver" is more comfortable, handles better, faster, and is better on gas or at least 3 out of 4

The difference with audio equipment is that it is personal preference and having a personal preference for "old" equipment does not necessarily confer a loss or detriment to any of the other aspects of the experience like an old car.  Definitely digital is far more user friendly than vinyl, and I would have a really hard time giving up remote volume control, but other than that, an old amp or new amp, old turntable/new, etc. takes the same effort.

On DACs, there is a following that is essentially going back 30 years in tech, and they are happy about it. Others like Erik lean towards a different preference.

Oh collection?  About 5 or 6 years ago, I came to the conclusion I had too much stuff in my life that was just "there" but not really making me happy and taking up space and time.  I scaled back to what I use and got rid of the rest. I can't say I miss it at all. I had a collector mentality in the past. I don't any more.

I don't think old gear is outdated or useless, but I do think old DAC's (before 2015) are severely outclassed by most modern equivalents.

In terms of amplification, tubes hold up a little better than solid state in terms of sound quality differences. 

PS - I meant tubes. :)

So if old gear is not outdated or useless....perhaps there is hope for me as a person?

Audio gear, like most watches and most cars, is a really bad financial investment.  I'm having a very hard time thinking of any audio gear that has even kept up with inflation, let alone appreciated.

In terms of gear to keep around, I accumulated a lot of junk and eventually sol it off as a lot. None of it held up particularly well, except for the Theta Casanova.
What got me off that merry go round was having exceptional end of the road speakers. That forced my hand in investing in a solid modern amp.

Now though, if I had the space and money I think it would be nice to have a collection of mid to small integrated amps, swapping them out every month or so for fun.

Theta ProBasic III still a great DAC.

The best-selling tube amp is still the Dynaco ST70! Still very desirable despite competition from Ch*na! Like vintage US cars it is easily "hot rodded"! I have one with a different input/driver board. It can drive the Quad 57's very well - and safely!

True, modern cars may have superior specifications and features, but that does not necessarily translate into a better driving experience.  

Not to mention my Ohm Walsh Sound Cylinders and DCM Time Windows driven by James Bongiorno's Sumo Andromeda amp! 

I have two pairs of Quad 57's and a pair of the Roger West (Sound Lab) designed KLH Nine full-range electrostats. Both these speakers can compete with today's over-priced five-figure offerings! Add my original built-by-Julius Futterman H3 and H3aa mono OTL tube amps and the resultant sound quality is SOTA!