All financial institutions will greatly benefit by sending less to the browser, not more. CAPTCHAs as we know are not foolproof, and should be limited. Instead, things like session/ip based hashing of field names, generating anti-csrf tokens and the like are trivial for the backend.
The vast majority of complexity in most projects is needlessly self-inflicted. DRY is dead, less-is-more is dead.
Let's Include All The Things is how Amazon became as pathetic as it is for a major commercial website.
I suppose it depends how you interpret the term web developer, since that's what simfoo was discussing. Myself, building browser-based games isn't web development, it's game development, which I feel is an entirely separate domain. Building a website, you really shouldn't need more than a day to put together the HTML, CSS, and JavaScript. The front-end of the majority of most websites is very similar. Normally, this would indicate regular code reuse or warrant a framework, but as indicated in my original post, I haven't found any framework that actually significantly speeds up my development time.
"Less than a day" for "complex" web sites using nothing but raw JavaScript and hand rolled HTML & CSS does sound unusual, both in terms of the result as well as the workflow. Given the verbosity of JS DOM manipulation, I can't really envision a particularly good reason to go down that route for anything but the most performance pegged web applications.
These tools are crazy helpful in that regard.