That is not fully accurate. "the works" - 'the' is not a noun. "Works of art" - 'of art' is not a noun. "Works in process" - you would not say "work in processes", you instead pluralize work to works.
'Work' has more of an abstract meaning, like teaching or furniture - but that does not mean you can't or don't pluralize them. Teaching is an important job; the teachings of Jesus Christ, etc.
The only time I've ever heard people say "works" (when they're referring to jobs or tasks) is if they're a non-native English speaker. I've heard this from native German, Chinese, and Japanese speakers, but never from a native English speaker, because the only time "work" is countable is in "work of art".
Roadworks is not really plural, it's just one word. You can't say 5 roadworks, for example.
Fireworks can be plural (if you're talking about the device itself) but again, it's still one word.
My goodness, so many native English speakers who don't understand their own language properly. Of course you can pluralise "work". You can pluralise most uncountable nouns, when you intend to refer to multiple bodies of said uncountable noun. Try stretching your mind using your imagination :)))