Would you spend you money on modest brand new car or rather buy top notch vintage one?

Used or refurbished works well in my experience. It all depends on the source. Music room or Safe and Sound are excellent sources. 

I have a buddy who is into vintage muscle cars. I have heard his horror stories about breakdowns. In my vehicles as well as my stereo system I want reliability. I have had friends over for a listening session and had something go on the fritz and ruin a great time.Having learned the hard way, I have built redundancy into my system so if anything goes down except for my speakers, I can quickly get us up and running again.
So let’s tackle your question directly. I have no problem buying used gear with some caveats. I will never buy a used phono cartridge. I will not buy speakers or amps more than 10 years old unless the capacitors have been recently replaced. Digital gear is changing so fast that last years best might not have the performance of the latest and greatest. You really have to look at the price. Something less than five years old at 50% off the original msrp I would consider. Same goes for speakers.Cables are in a different category all together. I have been delighted by some of the used cables I have purchased at terrific discounts.

This does not make much sense to me because vintage cars can be a multiple of a new model, assuming the marque still exists. In audio, some vintage equipment is highly prized and quite expensive- think WE anything, EMT tables, Studer mastering decks, vintage big horn studio monitors, etc.

What are we trying to focus on?- I was able to build systems more cost effectively in the period 1970 to say, the oughts of 2000 via used equipment. Once we got the supply chain whammy, no chips, existing equipment that you could get NOW became more expensive. I don’t think you can generalize- a specific piece of gear may be a grail or a trip to the dump. Ditto, certain cars. Old isn’t always good, but some history there too.

What are you really asking?

For the question as asked it would depend on if I'm trying to get best performance or a cool piece if history that still performs well. I think the value is almost always used for audio equipment,  just how used do you go, and what you consider vintage. Reliability can be better new with electronics, but I think you need to have a plan for good technical support either way.  You can hope for the best used, or you have to learn about the manufacturer, design, components reliability, support, and parts availability.  As mentioned depends on the type of gear. I just got a tube amp that's 25 years old. It's a great amp for any year built, and not a quality level I could afford new. It's point to point wired and will pretty much be repairable indefinitely by any good tube amp tech with no printed circuit boards in it to go obsolete. Mine's in great condition,  but you can be anywhere between like new and a fire hazard, so you have to be more knowledgeable to go vintage, which is a burden. I bought a great used DAC at one-third of new price about 5-10 years old, but I don't think I'd want a vintage DAC,  if they exist yet. 

@wart That is fine if you don’t get it. You don’t have to respond back. But at least you should get the message that we are NOT TALKING ABOUT CARS as you can tell from the subtitle. The title was constructed as a catchy phrase in order to get your attention. When it comes to WE, Studer, Nagra EMT etc., they are not affordable used equipment option for most of you and we should ignore them for the purpose of this discussion. So, you see, it is not that difficult to get it unless you want to be on top of things and control the situation. Relax and smell the roses - can you get that?