Yes they can. Things can be pre-loaded in the background. Data can be queued. Storage can be local. I know you can find some package or framework somewhere that attempts to do these things in a web browser, but its all hacks. Stateless HTML is not a application development platform.
> I feel like SMBs are the target of web-based mobile frameworks
Sure, that's possible. But there are also people creating native frameworks to put SMBs into apps. Magazines are a good example. The big publishers are making their own apps, but they're are also working on frameworks to deliver other magazines. Then there are non-publishers like Zinio that are making the platform for any magazine to be published.
> Is it worth the time and cost to create native front-ends for iOS, Android, BB, W7P?
I'm not arguing that everyone who wants a blog needs to write their own blog software. No, obviously they can use something like Wordpress, and let WP worry about the programming and compatibility, and they can concentrate on content. Same goes for apps. I'm simply saying that native apps always were superior to webapps. People forgot because it became so easy and cheap to churn out functional web code. AND because these mobile client devices were closed off for development for so long. Love him or hate him, Jobs opened up everything with the iPhone SDK.
I think the expectation of a company to have a native app today is equivalent to the expectation that they would have a website in 1997. Back then it was a very expensive proposition. Today EVERYONE has a website. Tomorrow everyone will have an app. Doesn't mean they have to hire their own software team to build it from scratch.