I know. One should change things one can change, one should accept things one can't change.
But, Fusion 360 is a tool. A tool somebody sane (hopefully and very likely) is in charge of to decide which features to implement and which features to leave out.
Moving construction steps from the (top) component to a give other component can't break future things, as long all the steps in the timeline are created in one component and include every construction step till the end of the timeline.
As long Autodesk has not F..ed up the Fusion 360 software architecture completely, I can't see a technical reason to implement this. It's just a replay of all the steps with on an other component. The only challenge I can see now, one will need to do some projections on every sketch. Finding the sources of the projections might be challenging, but for sure not impossible. It's just replay the steps on a different starting point.
Especially considering Fusion 360 once had a collaboration feature similar to multi user source code version management. This I can imagine is a nest of poisonous snakes and scorpions.
I am currently writing this after I found this post for the second times in this week being in exactly above described situation (construction till late into the night, better morning).
It's really frustrating to realise: it's nerly finished! Hey, let's start again!