Monetary cost for a gameplay mechanic like maintenance is just a fake argument.
As Flat and me and others have pointed out before:
Underneath the game is an economics simulator. The factions, the stories, the missions, the equipment you put on your ships, the living, breathing, background action in the universe, comes out of an economics simulator.
Now, remind me again why "it costs money" is somehow "fake" in a game where that is true?
Any game mechanic that the player doesn't interact with is pointless.
Many game mechanics won't be interacted with by many players. Players who fly around in one or two ships will never use the formation designers or the project/pipeline-management. Some players will probably fire a couple of mining probes at an asteroid once then forget about it.
As with other things, the point of saying "you can automate it" doesn't mean "you won't interact with it at all." If you're in charge of a big ol' faction, it is of course very important that your hulking fleet of crusty transports is sucking money out of the corporate bank account because they cost too much to maintain, are fuel inefficient, and too big for the runs you do. It's a powerful incentive to junk those and get yourself some ships that are better suited for the job. That you can manage that at a macro level, or go and buy them yourself if you really want to, isn't saying "the player won't interact with this mechanic." It's saying that the player doesn't have to micromanage at every level during their interaction with that mechanic. There's a difference.
Usefully, that process also creates demand in the system for all those other factions that make ships and the materials that go into ships. Which is good because see prior point about the economics sim that fundamentally, even if you never go near it as a player, is what makes all the missions and stories and stuff fun, or not, depending on its level of complexity.
I presume you don't want to be doing ore-runs for the whole game?
If your factory trader is down to 97% efficiency that's no reason for an emergency visit at the nearest shipyard.
Er... Fighting is hardly the only thing people will do in this game. It's not Tie Fighter.