This is absolutely false. The implementation is everything.
What creative things do you do?
I write poems, lyrics, song words, and so forth. Thousands of 'em, maybe over ten thousand now, since not long after I was old enough to write.
I design and write all sorts of stuff for my D&D games - homebrew settings, adventures, rules, maps, you name it.
I play* music with some guys, some of it freeform-ish (we come up with a tune /melody on the fly then write words for it, flesh it out, and add the words in), some of it pre-written; about 98% of it original, the other 2% are either straight covers or Weird-Al-like rewordings of others' songs. Up to about 40 hours worth of finished (if highly-variable quality!) songs now, if not more.
I used to draw until I realized I just wasn't any good at it, and packed it in. I'm also useless at painting, as some of my poor embarrassed minis can attest!
With the poems-lyrics and the music, the implementation and creative pieces go pretty much hand in hand, but are IMO still separate things: the creativity is thinking of it and the implementation is actually playing it (or, sometimes, getting someone else to play it - I can come up with what I think are some pretty good guitar lines or riffs in my head but can't play guitar worth sheeite, so someone else has to play 'em).
With the RPG stuff, it's often a variant on the old saw "15 minutes of creativity packed into 4 hours of implementation".
* - well, not so much lately; covid kinda killed it for us. We'll get back at it one day....