Unpopular opinion: I fully believe that anyone who says "code was never the hard part" was an irresponsible coder who perhaps never had to work for themselves.
No matter how long you spend on architecture, no matter how carefully you plan your features, if you are an actually good developer there are choices that emerge only from the first draft of the code — things that you could do better, broader ideas that suddenly emerge and change your view of your own work, abstractions that become possible once you internalise the project through writing it, realisations that a requirement is unscalable, unworkable or unsafe, etc.
Nobody ever finds all those things only in the planning stage in any piece of code of consequential size or functionality: if it was easy, we'd all be doing waterfall development like 1970s consultants or using StP like 90s consultants, and none of those other ideas about coding would ever have emerged.
LLMs will just write the code. They will never have the rest of that experience. And I think any coder who doesn't have a visceral feel for what I said above is just bad at it.
"The code was never the hard part" is just edgelord AI evangelists masking denial with a pithy mantra. The code, its capabilities, the tooling choices, it's all indivisible from all the other hard parts.
But then these are often also the people who think they can use AI song or image generators to do the bulk of the work and "add the finishing touches". They also think "taste is all that is left" when the thing that gets us paid is not just our taste, it's our responsibility for and to our work.