Spare capacity is something you want to see for the overall economy to be able to absorb increases in demand, but it isn't in the best interest of individual foundries as they'd rather sell all their capacity and run at 100%. Just another example of tragedy of the commons.
There are multiple ways we can align incentives such as "The Government" saying they will buy Wafers at a low price, to guarantee a minimum demand, but they are a customer of last resort* for X years, where other "Private" companies can buy the wafers at a higher price and they get priority.
Of course in such a situation "The Government" can get expeditated service for things like military by paying more. Likewise we as a society can actually build public foundries much like we have built public hospitals, public schools, etc. There are many solutions to "this problem," but hey this is not a new thing we been debating this stuff for at least 170 years ( actually far longer, but I am thinking of a specific Thomas Carlyle's
phrasing of "this problem." )
It sounds like market forces have handled the industry fine over the years, so it's silly to think they won't going forward.
This is highly debated. I have an opinion on the matter but for simplicity sake I am just going to point to graphs.
By Skanda Amarnath and Alex Williams Many thanks to Hassan Khan for helping with this piece
employamerica.medium.com
I am pointing at the graphs for you can argue if "the facts" are good or bad, but the boom and bust cycle was on one trajectory and then suddenly changed for almost 20 years after the the stock market crash and inconsistent demand and this in turn produce inconsistent supply leading to boom and bust. The ram market and the other market for silicon does not like this uncertainty, it is wasteful, and it does not lead to lower prices.
Maybe it seems non ideal to anyone who really wants a GPU right now, but any investment into building more of those is money not invested into something else. To someone who cares nothing for a desktop GPU that just looks like wasted money.
This last bit is flat out untrue, yet it feels like a truism. Humans deal with "waste" all the time, I may grow, buy, and plan to eat the strawberries but not eat them fast enough before the mold gets to them. Likewise we have also another form of waste where we never invested in the first place due to uncertainty. Both of them are not "excellent" they are an excess of doing too much and an excess of doing too little. No one can predict the future, not even the market.
The market is a reactive force, not a proactive one, and it is very good at being reactive for certain types of problems but not others. (and that is okay, markets can still be good and useful even if they have limits.) It is just important to know the limits the pros and cons of the situation.