This is true. But then you have an even worse problem -

So options to craft/upgrade have been made available to the player, and the game is linear, so the players gonna want to get "all the content" and the dev will probably want them to do that, too. Turns out the costs increase massively with each Level+ of upgrade. But because the content is simply there the player will and should feel somewhat obligated to perfect their gear. In order to add "interest" or something, devs decided to make each tier of upgrade for each item have wildly varied and always increasing costs, without wildly varied and increasing improvements...

Then the linearity comes in. Previous tier+all upgrades = totally obsolete, I think by just a few points in the case of armour (except maybe in the rare case that corpse run needs a boost). This stings twice as much if the player was pursuing really costly upgrades, which it just... seems wrong to tell player not to do. You can't even display armour, and devs stated no plans to do this for current roadmap, which just seems really strange.

Basically, costs need to be proportional to upgrades. This can be done by either (1) fixing upgrade costs or, more excitingly, (2) having upgrades confers benefits to gear other than just # improvments (resistances, set bonus tag, etc.). You could even have upgrade trees for gear. This makes crafting a real ADVENTURE! "This is my Poison resist bronze mail that is really good for Swamps," "This leather helmet has Deer Antlers and does JUST enough counter damage to kill a Deathsquito so I bring it to the Plains," etc. All the old gear can have niche purpose this way.

Alternatively, maybe the devs want obsolete gear and useless upgrades because they intend for the game to be a linear experience... which is fine... but a lot less interesting by the 3rd/4th playthrough for me, and for my friends, before the game even really began