Handholding is an issue which is affected by 3 factors: the model, the tooling and the human expertise. Out of the three, the last is the weakest link, due to the fact that it takes the longest to nurture.

Once tooling (e.g. agent harnesses, external tools) becomes more mature and consistent, the other 2 will become less of a bottleneck.

If I were to take a gamble here, I would argue that development will at one point reach the more ideal scenario, whereas the project planning, the scoping, will become longer. Also, the documentation section will take almost the same as the development, slightly longer at the edges.

The new ai-assisted era will most likely push companies to adopt a Waterfall management, rather than an Agile one.