Local mining isn’t a “plan better” thing. Local resources are limited, or at least were when these changes went through, and CCP very specifically doesn’t want any region of space to not have to import any materials so compression still has significant gameplay value from that perspective.
In short, minerals are intended to be moved around by an intentional design choice on the part of CCP, intermediate components are intentionally not. It’s why they take up so much space, often more space than the packaged size of whatever finished product they go into.
The thing you may be missing here is that having the game be “economically large” has value. What I mean by that is there is a significant amount of time and effort required to get a large volume of minerals or components or ships from, for example, Jita to Delve or from Delve to Jita, or even from Hek to Jita. That’s why components aren’t easy to transport, it’s why minerals aren’t compressed by default, and it’s why we don’t have massive Freighters that can carry tens of millions of m3 in finished goods all at once.
This sort of logistical difficulty is what makes the Eve economy granular rather than monolithic with different prices between trade hubs, and creates things like supply shortages for deployments in Null or mineral gluts in one area of space while there are shortages in another.
If you want to argue for much easier transport of components you need a reason why breaking this, even to a limited extent, is desirable and won’t actively cause issues, like for example someone manufacturing all their components in safety, compressing them, and then transporting those because they’re now better compression than minerals. Or instead of transporting a bunch of ships for a deployment, moving all the components most of the way and then building the ships there to save jump fuel.