So we become jaded. We get to think that anything is possible. All that's needed is for a few bright engineers to decide they'd like to do it. And all they need is some venture money, which is not hard to come by. We know the pattern.
Some engineers get an idea.
If their company won't back it, they gather a few friends. Maybe they hire a few people they think can help. They write a business plan and show it to a few venture capitalists, who put up some money. They develop a prototype. The VCs like it.