I've loved 80s/90s Japanese cars since the 80s/90s, then got sucked into the social pressures and spent 5-6 years in a couple of different brand new cars. Last year after a horrific experience with a brand new VW (3 page list of repairs and replacements in the first year of ownership, they bought it back off us), it hit home how screwed we are when a modern car breaks. They're so complicated now, with so much electronics. They even steer and park themselves. You can't tinker with them, tweak the ECU to your liking, or fix things yourself. There's some you can't even service yourself: https://en.wikipedia.org/wiki/Volvo_YCC
Now I'm back in 90s cars. Something breaks? Buy the part on eBay and swap it out yourself. Anyone can do it really, they're such simple cars. They're still comfortable, have aircon, generally higher quality than modern cars, way cheaper, and they can't ever track/sell your data.
They don't even need to be 50 years old.
80's and 90's Japanese sports cars are my cup of tea, and mainly for the reasons you state. Even vehicles from the mid-to-late 90's that had OBD II connectivity are still relatively easy to fault find with. The ECU's are fairly basic generally, there's no outside connectivity apart from the obd port, and even if it's running a basic CAN-BUS in the vehicle, they don't usually have any DRM style nightmares in this era.
It's interesting too, that a car like a KP61 Starlet from the early 80's can achieve similar fuel efficiency as modern small cars, because what they lack in emissions control systems, optimised combustion chambers or direct injection (as examples), they make up for with a substantial lack of weight. (Mainly due to a complete and total lack of safety features haha!).
Though I think there's a lot to be said for keeping old cars running. You're not expending resources to build new batteries, mill new steel, and not contributing to landfill (or recycling byproducts and waste). I don't know what the direct environmental comparison is between running a car for 20 years and building a new car every 3-4 years (as is the common purchase cycle), but I would be under the impression that it would be comparable?