Not at all--I'm saying they'll take steps to protect their investment. Those steps will be more cost effective, and more imaginitive, than the government could take under similar circumstances, because they know the actual dollar value of their risk, and the actual dollar costs of their efforts.
By way of comparison, the Apollo program cost about $100 billion in today's dollars. In 2004, a privately-built craft achieved a suborbital spaceflight for a cost of about $25 million. What does that show? After all, my cellphone has more computing power than NASA did in the 1950s... well, that's exactly the point. The free market could have achieved spaceflight whenever it was deemed cost-effective. Today a wealthy hobbiest could--and did--bankroll the whole thing. But Kennedy decided he wanted to go to the moon then and there, and he could--and did--forcibly take about one gulf-war's worth from the American people to fund it. That the money could have been better spent is proven by the fact that the free market didn't decide to shoot for the moon on their slide-rule technology.
The application of this parable to missile defense should be obvious. The reason you think the idea so risible is that you imagine there's only one way to do it, and that the government's amazingly inefficient way is it.
Future generations will find the whole SDI thing as funny as we (should) find the Apollo program: it's impressive what was accomplished with primitive technology, but funny when you realize that inside most people's 22nd-century iPods is everything you need to disarm a 21st-century warhead.
And when confronted by an aggressive state like Nazi Germany or Soviet Russia, or these days, a nuclear-armed Iran .... what, precisely will those "cost effective and imaginative" steps be? One thing is certain: it costs a hell of a lot of money to take your "imaginative steps."
Your General Re Defense Division is not going to build its missile defense from scratch in a year ... it's going to have to anticipate attacks years in advance if it wants to have any chance of countering them when the time comes. And so it'll have to shoulder a persistent military burden powerful enough and modern enough to respond to threats when they pop up. The standing army raises its ugly head once again, only this time there's no civilian oversight beyond what the Board of Directors think is good for the bottom line.