If USD devalues too much (but is still reserve currency), other countries will become richer aka, they can buy more dollars for fewer of their own fiats. Which means they can import more oil by converting more and more of their fiat to dollars. Which means demand for oil internationally will go up while supply remains about the same, causing price of oil to go up, regardless of where it is produced.
If USD devalues and other countries decide to abandon the dollar for trade in favor of say Oil-coin, US will lose access to international oil until it "earns" oil-coin somehow. How does America earn oil-coin? By exporting something. Since America can produce so much oil, the producers will try to export oil for oil-coin. Which means increased global demand and thus rising prices again.
US could shut down all exports of oil and only use it domestically and shun oil-coin entirely. But this means that
a. US can't import other things because of lack of oil-coin. So we will suddenly have severe shortages. Oh a bad disease in one year caused all potatoes in America to die? Tough luck sustaining all the food processing and chips companies. They can't do a stop gap import potatoes since we don't have any oil-coin. You can expand this experiment to all kinds of things such as stent-valves, rubber for tires, coffee. Our rich lives are truly there because other countries are working for it.
b. US energy supplies will be limited by domestic production and domestic supply and demand characteristics. Oh, we have such a great economic boom that increased oil demand but a few oil wells are down for repairs a few quarters? Boom, spike in oil prices again despite being self-sufficient. Another recession beckons since industries can't function with such high oil prices.
This globalization thing is not very simple. It may have caused a lot of grief, but it's also a very good distributed system that's preventing us from going back to shortages like medieval times. We're not dying just because there's a 2-3 year span of famine any longer because there's always somewhere else to get it from.
In the oil price example, drop in value of USD could cause prices of oil to increase (by how much? We don't know. There are entire commodities industries who hire quants to figure this out every day).
Assuming price of oil increases by 10%, price of chicken feed would increase by a%, causing an increase in price of chicken by b%, causing an increase in price of shipping chicken from farm to factory by 10%+a%+b%, the factory whose workers need higher wages now (by a total of c%) because of higher cost of living, factory will now have to sell their chicken for 10%+a%+b%+c% to a shipper who will need to pay another 10% who will pass this cost on to McDonalds who will have to pay 10+a+b+c+10 to get a chicken patty.
The dollar menu suddenly become a $5 menu.
As contrived as this example may sound, this is the reality in many "emerging" markets and smaller developed markets. We are so oblivious to real inflation and price fluctuations simply because we are used to getting stuff for cheap from whereever it is available because we can import any time. No shortages for any industry or any consumers here.
While I agree that having healthy domestic manufacturing is good, we need to be careful what we wish for because losing the reserve currency status is the last option of them all. It's truly devastating and you only need ask United Kingdom and how they lived for decades with rationing in order to pay debts and earn foreign reserves.
https://www.statista.com/statistics/204740/retail-price-of-g...
https://www.macrotrends.net/2548/euro-dollar-exchange-rate-h...
> We, and also other countries, can have fairly big currency changes without much internal inflation or deflation(can depend on country size). A number of countries have actually deliberately devalued their currency in order to encourage growth.
This is all applicable to the reserve currency or massively exporting countries. Not to importing countries, which the US is. The US cannot stop importing without causing massing inflation at the retail counter. No more $10 t-shirts and $100 sport shoes if they are made here.
I would recommend reading the article to truly understand how subsidized our lifestyle is.