It 100% is not the most unrealistic thing in the game, trust me

You might feel it is, but maybe that's because you don't appreciate just how unrealistic other things are. That's not a criticism; we all only know what we know.
I'm in favour of more immersion, but not more immersion in a way that unfairly punishes those of us that love the game but are relatively time-poor. I also don't think this makes the game any harder. It just means i have to spend a lot more time doing repetitive tasks. Is that the definition of challenge? FDev should be thinking of ways to add interesting things to do with bigger ships once you get them, not making it harder to get and maintain them. I want the potential to earn epic rewards for epic risks, rather than just the opportunity to play it safe for a regular income.
It's not so much that it would effect me now - other than occasionally switching out my loadout for fun - it's more that it completely undermines my aspirations, which is probably worse. I was working towards a Python precisely because I could use it for all sorts of different things. I do a lot of combat right now, and I feel I've seen that side of the game. I was looking forward to trying a bit of everything. With this proposed change, I'm facing doing a lot more of what I'm doing now (grinding out credits) just so I can spend far less time trying out those different things.
I use ED shipyard, but people posting that whilst asking for realism makes me laugh. I mean, you want the game to be more realistic, but you're proposing alt-tabbing out of the game to visit a website to check potential configurations?

That's not great for immersion.
I'm not against it getting harder. I'm not against more of a challenge. I'm just against increasing the grind. That is all this change will do. Either that, or it will force people to play more repetitively, and less flexibly. Both negative game-play changes.