Over the next 15 years, the American auto industry will face a death spiral of epic proportions that will lead to plummeting demand, cratering profits and slumping sales. Car dealerships and sales of traditional gasoline-powered cars will both evaporate.

Those findings are delivered by a research report released earlier this month from analyst firm RethinkX, co-founded by analysts Tony Seba and James Arbib. RethinkX prides itself on reading the tea leaves on how truly disruptive technologies -- like cellphones and solar panels -- can be on incumbent industries.

The report says that in 2021, when the authors predict that automated vehicles will be approved for widespread use on roads, a disruption point will happen. And from that moment on, using cars as a service will become cheaper and cheaper over time, thanks to automated car technology, electric vehicles and the ability for anyone to swiftly summon a car with a cellphone.

As a result, owning cars will fall out of style. By 2031 automated and electric vehicles driven as part of a service will make up 95 percent of the passenger miles driven on the roads, the report predicts. At that point, traditionally owned gasoline-powered cars will make up 40 percent of the existing vehicles in the U.S., and the amount of overall owned vehicles will drop from 247 million to 44 million.

Close to 100 million owned vehicles will be abandoned, according to the report, because it will just be that much cheaper to opt for "transport-as-a-service" (TaaS). An average American family will be able to save $5,600 a year in transportation costs by using transportation-as-a-service compared to owning a car, the authors estimate.

Those costs savings will come from both automated and electric vehicle technology. Electric cars can deliver “10 times higher vehicle-utilization rates,” 500,000-mile vehicle lifetimes and lower maintenance costs, according to the report. Automated drivers can eliminate human driver costs and lower insurance and maintenance costs.

It’s not that hard to imagine that aggressive scenario down the road in densely populated cities like New York. Last year alone, companies like Uber and Lyft drove 500,000 passengers per day in New York City, which was triple the number of passengers driven in New York in 2015.

Electric vehicles, too, are clearly coming down quickly in price thanks to dropping lithium-ion battery costs. The analysts at UBS predict that electric vehicles in Europe will cost the same as gasoline- and diesel-powered cars next year.

The sticking point might come in the more suburban and rural areas. These regions are spread out and have lower population densities, and could have higher costs for passenger miles. But the RethinkX report says that adoption is likely to be more extensive than generally forecast in the suburbs and even in some rural areas “because of the greater impact of cost savings on lower-income families.” The report contends that only the most rural of areas could be left out of this transformation.

So what does the auto industry look like in this world dominated by automated and electric transportation-as-a-service companies? Well, it’s not pretty. “We are on the cusp of one of the fastest, deepest, most consequential disruptions of transportation in history,” as the report puts it.

For automakers, that could mean a severe death spiral, similar to the one that some predict for utilities. “Individual vehicle ownership, especially of internal combustion engine vehicles, will enter a vicious cycle of increasing costs, decreasing convenience and diminishing quality of service,” the authors write.

Car companies that continue to focus on manufacturing traditional gasoline-powered cars for traditional ownership models, as well as auto dealers and insurance companies, could face “total disruption” and “almost complete destruction.”

All car companies are well aware of these trends with electric and self-driving cars, but most are probably not expecting this kind of disruptive intensity. The report predicts sales of gasoline-powered cars, the value of used gasoline-powered cars, and car dealerships will all be utterly destroyed.

So if you believe the swift death of the auto industry is coming, what’s a car company to do? Adapt, embrace new technology, and hold on tight.

Companies that are in prime spots to benefit from this transition include automated vehicle tech makers like Tesla, Nvidia, Google, Uber and Baidu. General Motors and Ford have also acquired self-driving car tech.

But the consumer will likely identify more with the provider of the transportation-as-a-service than they will with the carmaker in future. So the brand dominance will shift to the tech company, the report argues.

Leading electric car companies will have a lead as well, such as Tesla, GM and Nissan.

The report recommends that car companies do the following: acquire automated technology, invest in electric car models, consider providing transportation-as-a-service for consumers, halt major capital investments and R&D for gasoline-powered cars, and look for alternative revenue models.

Already, the auto industry is seeing disruption of some sort as it tries to shift toward transportation services, automated technology and electric vehicles. Last week Ford announced that CEO Mark Fields will be replaced by new CEO James Hackett, who previously served as chairman of Ford Smart Mobility, a subsidiary focused on emerging mobility services. Meanwhile, the company plans to cut some 1,400 jobs.