Can't replace the currency of a power if you're subservient to it.

because Europe is American protectorate

To oversimplify, the EU is vassalized by the US Empire and is dependent on it. The US floods the world in dollars and uses this to "tax" the world as a debtor country. The global south isn't interested in trading dollars for euros. If anything, the yuan may become a new reserve currency in the coming years as Iran is accepting oil through the strait of Hormuz in yuan.

In addition to what others have said the EU doesn't have fiscal authority (it can't tax and spend) and relatedly can't issue "Eurobonds". Both of those are likely terminal blockers for a would-be reserve currency

Only one oil country switched to Euros and an invasion switched it back to dollars.

A lot of the international banking structure was built on American systems of banking, so the dollar got baked into a lot.

Until Trump, the dollar was generally seen as more stable given its longevity and being the currency of the largest superpower.

Also, compared to the Euro and Yuan, the American dollar has an internal hedge when it comes to energy prices given that the USA can supply most of its energy needs by itself. It is hard to handle an oil shock when the currency's value drops because the internal market can't afford oil.

Reserve currency status is established and maintained through military might.

EU is unable to beat the shit out of countries that insist on using other currencies.

The Euro has a few problems that keep it from being a reserve currency. A big one is that it's not a centralized currency, since each EU member has their own fiscal policy. This creates a lot of risk with limited upside.

Europe also doesn't make enough stuff at the international level to need to get lots of Euros. Europe also doesn't seem culturally interested in being a global reserve and is more content being regional.

It should be chinese yuan, not the eruo. They are a developing superpower, on par with the eu already, and there currency is much more stable than the euro, or any other currency afaik.

In addition to what others have said, you have to run very large, very persistent trade deficits for your currency to become a reserve currency (in addition to obviously needing to be a highly stable currency). Of the only currency issuers that could potentially fill reserve currency role (US, EU, China), only the US is interested in persistent trade deficits in order to pump the globe full of their currency.

It takes a very long time for something like that to switch. The US took more than a century to integrate themselves into whole world. Every McDonald's or KFC is an extension of that control and thus the USD as the default reserve currency. All that has to close down first. That is going to take a long time even with the Stupidest President throwing US soft power down the toilet.

Shit like that doesn't happen overnight, bub

The time scale for those changes to materialize is measured in decades. We might eventually see a dedollarized world if the US continues failing spectacularly for the next few years. Right now things are still in "anyone's game" territory.

agree with @agentTeiko@piefed.social and also we are likely to end up with a period of multiple competing reserve currencies before a single dominant one emerges (which itself is not guaranteed in the near future)

Because the dollar being the reserve currency is a direct result of the US being the world hegemon. As the US is falling, and China is expanding trade but not asserting itself as the hegemon, the world is becoming multipolar.

The EU's economic situation doesn't allow it to become the new hegemon either, and their political fragmentation makes them unreliable anyway.

The concept of a reserve currency might be outdated because of that multipolar world. And if not, the EU is in no position to impose the euro, as China is way more stable and has much better economic relations with everyone, including both US economic allies and enemies.

There would be no contest if China tried to assert the RMB as a world reserve currency, but AFAIK they're not interested in doing that.