Sunk cost fallacy maybe. Not about money, but time. And the prospect of just getting to the same point. Which may or may not happen.
I know what you mean
But I play in Open (in the suburbs, not the high pop hotspots) and regularly meet relatively new players. They usually have around 2bCr, either a cutter or corvette, and are mostly harmless or maybe expert combat rank. They are just starting to get into engineering & are looking for a reason to keep playing after a hundred hours or so of play. I help those that are willing, to find a reason to continue to play, usually a cause to work towards. That then gives them reasons to buy & use different ships, for gathering exploration data, for hauling, for killing NPCs, and making their ships better at doing those tasks by engineering them for a better jump range or bigger shields becomes a natural part of achieving the goal rather than just upgrading for the sake of it. Most of my ships are cobbled together from spare parts, then tweaked to improve their capability as I use & assess them. It's not a big part of how I play.