If they know the slightest bit of PHP, they can do an
include_once('filename'); function. This is done a lot with
footer.html files. CSS can be pulled from a single file across many many pages of HTML, and if they are done right, effectively provides a "template" system. Images can be included as different sizes in CSS as well.
Alternatively, someone can set up a single PHP page with lots of static stuff, then pull the content (images and text) from a database.
Or simpler, they can hire a real web-developer.
"...Without a framework running on a webserver, without frames, and without WYSYWIG tools like Dreamweaver"
They don't need any framework, but without PHP or some sort of processing, there's not going to be any templating without copy and pasting blocks of HTML and changing the content. PHP makes it simple even for beginners to include many different files into one page. A CMS or Content Management System makes it simple for EVERYONE to have decent-looking and mostly-proper(ly) coded sites.
Dreamweaver isn't really a WYSYWIG editor; I mean, I use it personally for the syntax-highlighting aspect of it along with PHPDesigner. I think the graphical aspect of it isn't great though.
Refer here: http://en.wikipedia.org/wiki/Web_template_system for all the different types of templating for web design and/or development.