Jeff,

I think Matt's comment sums it up:

That’s actually why we decided to take a different business model approach with VaultPress. Most of Automattic’s services are freemium, meaning the core product is free with premium upgrades available. That just didn’t seem appropriate as we imagine how we imagined VaultPress evolving over the next 5 years — it’s a high-end product, for high-end users.

It's not intended for average bloggers/average WordPress users. It is intended for WordPress users who deem the value of the potential loss of their content to exceed the price point (which I've seen anywhere from $15 - $25 per month).

@donnacha | WordSkill -

Sadly, hot-patching cannot be part of the free WordPress package, because an ongoing monitoring and patching service requires serious resources. This service must be paid for, there’s simply no other way to get it done

Why?

If update notification (of core, plugins, and themes) can take place every 12 hours for every single wp.org installation in the wild, why would it be any great resource drain to allow site admins to configure their WP installs to automatically install core updates without their intervention?

Why would this functionality take any particular additional resources?

Unless you're talking specifically about VaultPress monitoring a site for (malicious) changes? And if so, aren't there plugins that do precisely that sort of monitoring?