I’ve been noticing more novel compound words. I just saw “freewill” in a book. My 1985 Macquarie Dictionary (AU) has entries only for “free will” and “free-will”. Is this a shift of a computer age? Maybe I see these compounds most in news headlines? Checking now I see a headline about “sunscreen” - and I’m surprised to find it’s not even mentioned in my old Macquarie! Nor is “sun-block”. Another in today’s news is “ceasefire” which has a hyphen in Macquarie. I wonder if hyphens drop out over time. #EnglishUsage
It's a pretty standard trend. The sequence from two words to hyphenated-word to oneword seems like it just naturally tracks the degree to which the referenced concept is recognised as a thing by the speakers.
If I say "sunscreen" I'm not thinking of it as a screen against the sun so much as just sunscreen.
I think it's just a natural drift that is only temporarily slowed by the friction of convention.