Think the whole 2.0 update with the materials first for the little enhancements and now materials and "cargo" for engineers introduced a mechanic in the game it was not designed for in the beginning.
These are "basic" MMORPG elements, horde everthing you find, as you might need it later on for crafting an upgrade or a mission giver. To do that all MMORPGS have the bank, some even go so far to have a magical bank to which crafting materials are automatically transferred when you pick them up so you do not need inventory space. One of the most often bought enhancements in these games are upgrades to you bank vault or on character inventory.
Elite as it was in beta and before 2.0 was 1 person in a ship flying around, hauling cargo from A-B, or blasting people out of the sky. There were no random drops of stuff that is mostly useless but for some very specific reason you have to keep it. So a bank system was not really needed. You bought cargo and you sold it in the next port. If a ship dropped cargo when you killed him or you went pirating disabling them then you picked it up and sold it at the next black market.
So there was no hording of materials needed the few missions where you needed to steal cargo were not gamecritical and could be ignored. So if you wanted you could safely ignore all the trading stuff and still have fun.
Horizons introduced the "weightless" materials found on planets, to accommodate that a "magical" bank was built into your ship to hold that which would even transfer from ship and survive destruction of your ship. But while the recipies from 2.0 were nice you could live without them. Guess many explorers or traders were happy to have 1 or 2 FSD charges to get out of a critical situation. Free reloads were nice but not really an issue as ammunition is often not that expensive. So it could be ignored.
But here was the first issue as you needed a ship with a buggy hangar to get to the stuff, which meant retool your built, often not an issue for explorers, but fighters with their few internal components often had their first problems there.
In Engineers it feels like some dev, thought people are not collecting as many materials as we want them they are ignoring that part, lets force them to do it by introducing an upgrade that needs tons of stuff, you can not get anywhere just find it floating around or on planets. So the magic bank got more options, and to make it worse they also need "rare" tradegoods you can mostly get from doing missions. So forcing people not only to hunt the galaxy for stuff floating around, but also needing to rebuild their ships or buying others to get the goods and carry them around as there is no storage. Moving the game from do what you want to the hunt and collect game style of other MMORPGS but without the underlying mechanics to support that kind of play as it was not intended that way.