I realize I can create a minified version of these files on my own, but that's not the answer here. It's clear that jquery-ui intentionally publishes minified versions of (almost) all its files, so the answer "you should be minifying on your own" doesn't make sense. There is a special 'minified' directory containing them. Same as most other software packages like jQuery, knockout, so on so on. The minified files are useful and easy to consume.
Question is -- why would jquery-ui publish SOME minified files but not all. By doing so, it makes it impossible to require in the 'widgets' because there is no 'minified/widgets' directory.
I really think this is just an oversight.
Can you please take a look at your scripts that publish to bower and include the minified versions of widgets?