Big companies better start seeking out people like tptacek and quick. More than just consulting, I think a Heroku-like product with a heavy emphasis on security (in addition to ease) could be a great product/SaaS.
Security is sort of an amorphous concept that most people just can't really wrap their head around. What does secure software look like? How do you know it's secure? Non-technical users have no way of knowing; expensive software is just as likely (if not more likely) to have security issues as Open Source software. Software that claims to be secure can be just as insecure as software that makes no such claims.
Security is a process not a product. You can't buy security. Things like proxies, mod_security, firewalls, IDS, etc. are all bandaids that you put over problems, and they're usually "preventing" ancient exploits that have already been fixed in the underlying software (assuming you're running the latest version). They might prevent some attacks, but if you're running insecure versions of your software underneath, a determined attacker will find a way in.
In short: Security is hard. The new hotness is easy and is an easier sell.