I don't want the white race to go extinct anymore than anyone else and there are certainly problems but it's not something we can really prevent. The real white population in America is about 55 percent. Statistics claim it's 76 percent but thats counting 21 percent hispanics whom are known as white hispanics.
The population is likely much lower than 55 percent since that figure also includes Arabs, Central Asia, Northern India, and Northern Africa as well which are very diverse in population. Many White Americans also have other mixture such as Creole in New Orleans and many whites also have small percentage of Native American blood in them and many others so that number is probably quite lower than 55 percent.
If you look at South America, this is closer to what America will be like in the future. Latin America is a mess, and much of the original population is pretty much wiped out or mixed now with record low numbers below 5 percent with the exception of Mexico which is still at about 30 percent though much of the original population has mixed with Europeans whom lived there for centuries. Crime rate and socialism is at an all time high there.
Europe on the other hand has been going through the same thing, if you look at Eastern Europe today, it's a mixture of different people and cultures. Slavic tribes inhabit most of the region but slavs are not a pure blooded people by any means either with some having a small amount of Germanic ancestry, some have Northern Indian in them, Gypsy, Jewish, or Turkic/Mongol admixture. Eastern Europe has always had more problems than Western Europe but then again they have also fought many wars to prevent invaders from taking over their land.
it doesn't help either that immigrants are coming into Spain, France, Sweden, Germany, and the UK and are literally becoming the majority so I think there is definitely something to worry about.