That could be it (or part of) the thought process behind the decision, assuming it was in fact a deliberate move. If I'm to have a bash at listing the possible reasons as to why there aren't city maps in Starfield, and in no particular order, here goes:
- Scope creep: The desired implementation was so ambitious that they couldn't complete it on time, and didn't want to release something that didn't fulfil the ultimate goal (e.g. a rotatable 3D map, like the ones in the Doom games from when Bethesda took over id software). Maybe they wanted to also track NPCs and add a whole layer of trackability depending on some skill or ability. Maybe they want to help you track resources which are needed for the various crafting mechanisms which appear on the map once you've encountered them (and before you explicitly track a particular recipe or research goal).
- Unfinished locations: The possibility that they intend to make topological changes to one or more of the cities in the future, or that the cities are not yet done. The cities are hand-crafted, the rest is "tiled" using handcrafted elements and procedural generation.
- Resources and priorities: They descoped it altogether to prioritise polishing the rest of the game as much as possible and anticipated that they will get complaints, and respond to said complaints by promising that it is something they will add at some point in the future because "we love hearing from you and need this feedback to help improve the game" etc.
I honestly don't think they forgot about it or that they had/have no intention of implementing it. I think they simply did not have enough time to get it the way they needed it to be on time for release. There might be some unfinished dream city maps implementation tucked away in the current release which just needs to be switched on once it is ready. It could be that they have "something" going on in there but they're not sure about whether or not it will sit well with their future ambitions for the game.
My bet is that they didn't have enough time to complete their maps implementation for the release and that there exists some indecision as to what they would consider to be an acceptable implementation. Perhaps they didn't want to present blueprint-style raster diagrams in a future where humanity has galactic reach, space-folding tech and have invested all their resources and research capabilities on creating all the things we need for the year 2330. Just no binoculars, rovers, Google Maps and interplanetary video conferencing and email.