An interesting point of debate, the outcome of which we will never know. I will say that three months prior to his death, Walt held a presser with Cali Gov Pat Brown, to announce the plans and support highway construction. The US Forest Service backed the plan. My contention is Walt's force of personality would have prevailed, as environmentalist opposition at that time had not coalesced enough to overcome the project's momentum.
https://www.yoresequoia.org/tag/walt-disney/
A new book about the issue has been published which I have put on my buy list.
https://www.amazon.com/Dawn-Mineral-King-Valley-Environmental/dp/0226816192
Dawn at Mineral King Valley: The Sierra Club, the Disney Company, and the Rise of Environmental Law
The road was already approved by the state, Forest Service, and National Park Service. I'm not sure Walt being alive would have changed the eventually stalling and abandonment of the plans. And part of the deal was that they were concentrating on WDW. Then NEPA went into effect.
Even as the Supreme Court handed Disney and the Forest Service a victory, another legal obstacle stalled construction. On Jan. 1, 1970, as the litigation was wending its way through the federal court system, President Richard Nixon had signed the National Environmental Policy Act, which required federal agencies to study the environmental effects of proposed actions in detail. Despite the high court ruling, then, work could not begin in Mineral King until the Forest Service analyzed the ski resort’s impact and published its results.
As the Sierra Club amended its lawsuit to conform to the Supreme Court's standing doctrine, the Forest Service prepared several drafts of its environmental impact statement. It released the final draft, a 285-page tome (nearly 600 pages, including appendices), in February 1976.
By then, Disney's proposal was more than a decade old, and the company's executive leadership — along with skiing enthusiasts and many in government — had lost interest in Mineral King.
Congress finally killed the project with the National Parks and Recreation Act of 1978. With President Carter's signature on Nov. 10, 1978, the Mineral King area became part of Sequoia National Park. Today, Mineral King Valley is still accessible by the old mining-era wagon path — now a one-lane automobile road — but most of the land once destined to become a mountain
Disneyland is now federally designated wilderness.
