I think there are "golden eras" to certain things. The conditions are just right, inertia builds to a head, and a product or idea-- or sport-- captures the public's attention in a way that it didn't before, and that it might not ever again.
I think the "golden era" for cars is past. That's not to say that great cars aren't being made or can't be made, it's just that the general public's ability to fall in love with a car, is more limited now, than it was in the 1950s and 1960s. There are a lot of reasons for that. There's more diversity in the marketplace now than ever before, more niche products that satisfy niche consumers. But that diversity also means there are fewer people available to fall in love with just ONE car, or just ONE classification of cars.
I also think that the love people feel for cars in general, has waned. They were once a symbol of freedom and hope for a better life. Especially sports cars and pony cars-- these played directly into the idea of the "open range." But people have a more cynical and jaded view of cars now. Many curse them for using precious resources frivolously. Many believe they should not be fun, but take a more utilitarian view. Gas isn't cheap anymore, oil is a finite resource, space is becoming more limited, and the idea of the single-driver car is being attacked from multiple sides now.
All of that to say, I think the "golden era" of the auto is past. We're not going to see automobiles capture a wide portion of the public's opinion in such an optimistic and breathtaking way. You bring up the Cherokee and the Prius, which are both disruptive to be certain, but they did so based on their function, their utility-- not because they captured the imagination of drivers across the globe.
Just my $0.02 anyway. I have similar views (but for different reasons of course) on the golden era of college football, and why the teams that rose to prominence in that era are still the helmets of today-- even if they struggle for decades-- and breaking into the helmets is extremely difficult and rare.
I do think that individual vehicles have to hit the right "mindset" at the right time to catch the public's love.
I think the Mustang hit the market at a very hopeful time for the US. We had the space program in full swing. It was before the late 60's struggles of the Civil Rights era and then Vietnam really took its toll on the American psyche. It was part of the postwar economic boom. The earliest of the baby boomers were turning 18 years old, and those right behind them were probably looking for "aspirational" products, but also attainable ones, and most of those in their early 20's weren't really of age during WWII to really have understood it. It seemed the world was their oyster and everything was sunshine.
You drop a little, sporty, stylish, affordable car right in their laps at just the right time? It caught fire. It created a new class of vehicle.
The same was true of the Cherokee. It wasn't really the first true SUV, but it was perhaps the one that hit at the right time in the market to not be a "utility" vehicle but to be a "car/van replacement vehicle", and accessible to the everyman. It popularized a whole new class of vehicle.
That's hard to do. It's hard to be new and be successful. Even many of our unique and successful cars are nostalgia... When the VW Bug was re-introduced, it was a throwback. When the Mini was re-introduced, it was a throwback. Those were both successful, but they trade on their history. Even the Miata, which grabbed a very unique and niche part of the market, wasn't "new". It's basically a little British roadster that just happens to be made by a Japanese company. Nothing about it was truly "new" like the Mustang or the Cherokee.
The same is true of the Prius. It appealed to environmentalists and frugal types who wanted to reduce gas consumption, but it's not that unique of a vehicle. It's basically just a small hatchback which gets great mileage.
The one recent one that I think has really "caught" has been Tesla. While the form factors of the cars aren't new, the performance envelope in which they operate is basically sports car territory in sedan/crossover bodies. At the same time, their one-screen operation (which I hate the entire idea of--I want buttons for common features so I can operate the car without looking away from the road) and OTA updates are unique. The people who love Tesla REALLY love Tesla.
But I agree that part of this might be a fleeting thing. The "golden era" of the automobile is largely contingent on the driving characteristics of a vehicle. I think that if automaters fully solve the autonomous problem, most of what we use to differentiate vehicles will go away. If I'm not the one pressing the accelerator, do I really care if goes 0-60 in 4 seconds or 8? If I'm not the one turning the steering wheel, do I really care how well it corners?
Automakers, with autonomy, might be engineering themselves out of the most interesting parts of their jobs--designing something that's different than what other companies are making.