Security is balanced against cost in a risk-based assessment. One of those factors is certainly bad publicity and lost sales, and that might actually be a fairly small number. But there are still other ways to weight the argument in favour of security. For example: regulatory fines, senate investigations, class action lawsuits, directors going to prison, cost of recalls, etc.

So although GM may not have much security pressure from the consumer, depending on the surrounding legal and regulatory environment, creating more secure cars might end up being a sensible move.

I guess what I'm saying is that I agree that currently there isn't as strong pressure for security as I'd like. But that can change and not just from the consumer/sales side.