How to sell Information Security ?

I am not sure about you but I face a tough time selling the importance of Security to people. This article by Schneier was very impressive and made sense to me. If you want Software vendors to deliver quality secure products, then laws should be passed to add liabilities on Software vendors for the Security holes they deliver. This way Vendors will be forced to comply and come up with Secure Softwares. I wish a compliance similar to SOX gets enforced on corporates so that Secure Softwares are developed and deployed. But there still remains the problem of the already delivered thousands of Software products and solutions which have failed to consider Security during the design. You can never add a layer of Security into any Non secure system and claim it to be secure.Deriving a solution to this problem would be really interesting rite !!