I disagree. Underrail has nothing of a roguelike, for example, the very stample of roguelikes are permadeath. There are other things too like procedural level generation, and while RNG exists and can screw you, RNG pertains drops or possible enemy conbinations you might find. When it comes to combat roguelikes are made of certainties. You know exactly what damage your weapon cause, there is no variable in damage rolls, at best there are hit rolls.
Now there do is at least a roguelike that uses money and a barter system now that I think about it and of course it has a limit amount of inventory space. it's called dungeons of dreadmore which I'm sure you all know it. So what happens in DD when you hit inventory limits? There is to ways to deal with it. The later expansions introduced a sort of home portal which is a place you can go from anywhere and you just drop items on the ground and use that as storage so you can sell everything. Nothing is left behind. Before that existed it was just extra work, you drped things by the stairs and kept moving the whole stuff even if it took 10 trips. Eventually you'd find a store and sell all. Just busy work when an infinite inventory would have beneficted the game much more... Sword of the stars: the pit had a limiting factor on that which was food but there was no money or traders so it worked well.
Now if there was a roguelike that had selling and money but money had ultimately no use, then money was not money, it was points and I wouldn't care as I don't play score attack games.
Now the current problem is not that traders buy too much, is that traders don't buy everything and that they pay too much for what they buy. The previous system was better where they paid less, you needed to repair items more often to get their money worth but it already paid too much much, at least later down the line anyway.
Idealisticly, the traders buys all and you have no carry limits. If you follow only the main quest you'll end up deprived of money, it shouldn't be impossible to beat the game but definitly make it hard. If you do some sidequests, let's say about half of them (assimung that a third can't be completed because you don't have the skills and you are always limited in which skillset you can have) then you'll get just about enough money to get everything you need, from ammo to equipment. If you doo all sidequest possible or half but explore then you'll have some extra money to throw around however you like. This is a very good system. it takes care of the money problem. There is no immersion break in having to stop midquest to go dump/sell stuff and there is no chore in even trying to sell the items.
Even from a realistic point of view (and again, realism takes a backstep to balance) you are a living in a world where you live off what you can scavenge. There are no worthless items, everything is worth money and money is a very precious commodity, especially now that the world has gone to hell. It makes sense that you'd carry everything and sell everything even if it took you time. You certainly wouldn't leave loot behind for someone else to get the money instead of you.
You can say that the current system tries to work like a roguelike where it forces the player to leave items behind, however it doesn't. the player always has a choice whether or not to take it, it will just take more time and break immersion. Selling items follows on the same page. You cannot stop a player from selling everything, you'll merely make the plyer waste several hours to be able to do so.
The leason taken from this is. A few people will like it. Some people will dislike it but still suffer the system to play however these people are probably going to finish the game once more likely just follow the storyline since they don't need to do more and then they'll never play it again. And some people will just be so frustated with the chores and disrespect of their time that they will give up on the game and consider it a waste of their money... Let's consider the previously implemented system where no one had complaints about it. Everyone liked it how it was, even if a few people like it better now, everyone liked the old system! The only problem was too much money floating around and that was very easy to remedy.