Mr. Hands

It's very late here, and I love this question, so I'm commenting to get back to you in the morning!

I don't know if I have a term I've seen before on this, but I would think of this as a kind of inflection point?

If you're thinking about kind of... (and: apologies for the terminology here) supply and demand of a particular resource in the game, and maybe even an abstract graph of the ratio between them, it sounds like you're kind of describing the point where supply starts to exceed demand.

I don't know if there's a name for it. As you pointed out, people play games at different places, some people like grinding, some people like exploring every optional path. I think it's pretty easy to tune the numbers and design it for one type of player, but it would be very difficult to design it for every type of player.
It's definitely not necessarily inevitable, but I think many game designers end up choosing to set the balance so that someone who just guns straight for the end of the game without stopping for sidequests or grinding will be reasonably challenged without running into a hard wall. It just minimizes the number of people who'll quit the game out of frustration, you know?
I think an excellent example of an absence (or at least much lower prominence) of this tipping point is pokémon nuzlockes, the resource in question being "viable living pokémon you have on your team". They're kind of unique in that anyone playing one is voluntarily setting the difficulty level of the game (normally much easier) to one that's satisfying to them. I think a game designed that way from the start would have a much harder time getting traction and being successful.
Maybe if there's a limited amount of currency in the world, and it isn't enough to ever buy everything?
Of course, more difficulty options seems to be a pretty straightforward answer to this as well.

I don't know about what it's called but it's not inevitable. Usually it's a thing when the game just kind of runs out of things to charge you for, intentionally and otherwise. You can extend the period before that point by introducing more expenses - the example given notes that Hollow Knight added some expensive things in a DLC, likely to make money mean anything later in the game.

You can design roughly when it happens by increasing rewards at a certain point and not introducing more things (or things at a higher rate) to spend money on. More income with the same expenses means you'll outpace needing to scrounge to buy anything.

I think in some games, this tipping point exists as part of a way to give the player the feeling they are becoming increasingly powerful and capable.

In the same way that being level 50 and oneshotting the enemies that killed you when you were level 5 makes you feel strong, having 5 000 000 gold and buying out all the high level gear, when in the beginning of the game you could barely afford potions, can make you feel really rich.

I think it's also just a thing that happens if you let the player acquire an infinite resource like money and use it to pay for a finite resource like equipment. No matter how hard it is to get the infinite resource at first, eventually you'll have more of the former than you need for the latter. (It's interesting to contrast this with finite collectibles, where it tends to be easy to collect them and get rewards at first, but the more of them you have, the harder it is to find the rest.)

Whether or not the general phenomenon of "too much money" is a good thing or not, I think really depends on the context of the game, as well as of the player's personal preferences.

Like in idle/clicker games they want to give you the experience of "hehe number big" so they want your ability to get resources to increase exponentially, but they also want to give you even bigger numbers to aim for because there's no reason to play otherwise. When there is no scarcity left the game is essentially over.

One the other hand, in something like an open-world exploration game, "being able to buy anything you want" may actually open up parts of the world you couldn't explore thoroughly before, because you have the resources to get through those places with ease. This can be a big positive for me. Scarcity can be a really fun thing, but by the time I've beaten a game's main story and played it for like 100 hours, I don't tend to want to be scrounging for resources anymore, I'm more looking just to run around the world and find the little secrets I didn't notice before without fear of dying or running out of something important.

In general I tend to run into this tipping point less often than most people because I'm not really into grinding for resources and I also don't tend to be interested in "optimal" play which would reduce the resources I would need to get through the game. I do tend to do some side content, but like, if the side mission says "get 100 of this item" I'm gonna come back to it 20 hours later when I happen to have collected 100 of that item from normal gameplay. I'm not gonna go out of my way to get 100 of that item now and then have more of that item than I need for the rest of the game.

In fact, when games provide ultra expensive things for late-game players, whether in the base game or through DLC, this can be a detriment for me. Like, I'm already satisfied with what I've done in the game, and you're telling me to go back and grind more to get that one last thing? That isn't fun for me. (I'm glad some people enjoy this but... really not my thing.)

Because of this sort of thing I think you can design where the tipping point is to an extent but only if you're willing to accept that your design will only work for certain players. I've definitely noticed that the only games I tend to have way more stuff than I need in are ones where young children are a large part of the audience, since on average they need to buy/make more things to survive, and they are also not as good at/not as interested in acquiring money/resources.

If you wanted another resource, this GMTK video does a good job breaking down how game economies work at a high level: https://youtu.be/Zrf1cou_yVo