On related note, Internet Archive backup would probably cost between 20M and 60M USD. Many EU countries would have incentive to do this as public culture preservation projects.
The archive is roughly 70 PB. Decentralized storage projects have achieved 7PB already. Thus attempting a decentralized backup would ALSO work.
There are multiple archive projects around the world, which often isn't understood when the Internet Archive (the biggest and original) is discussed.
Various countries including some EU already have those as "public culture preservation projects", targeting their own nation's web presence.
In that context, and with scarce funding already, there is not really an incentive to back up a load of irrelevant (in the sense it's not their country's) archive material.
Now, notice that the budget of many of these projects are X billions:
https://www.ne-mo.org/cooperation-funding/funding-opportunit...
Putting a 100 million EUR into an European IA backup would be more cost effective than any of these projects.
Alternatively or additionally:
https://en.m.wikipedia.org/wiki/Wikipedia:Fundraising_statis...
Wikipedia could actually also probably – being dependent on IA – invest 50M into the project. In fact, this would probably do more what the donations were meant to do than anything else they could do with the ("excess") funds.
Truth to be spoken, NSA probably has an IA backup. But it still sort of drives me insane to know that political change or natural catastrophes could lead to loss of public access to the IA. No one seems to care about IA enough except IA itself.
Current digital preservation projects are likely a tiny fraction of that 100 million on national levels and will include additional activities like those you ascribe to the IA, but carefully attuned to each nation's priorities while collaborating internationally with each other including organisations in the USA like the IA.
Importantly, they will also be operating strictly according to national and intra-national legislation (which IA has gotten into severe trouble within the USA).
In the context of a complicated international environment with many different local political, cultural, commercial and other factors, it's difficult to see how your proposal to replace local projects with an IA backup would be either more cost effective or legally practical.
The Internet Archive is inspirational and does a terrific job, but canning the many disparate entities that do national equivalents on much more limited budgets in favour of moving those funds to the IA (or any other global corporation or organisation) would risk invoking the classic problems of centralisation with associated detrimental effects on local requirements.
I am not sure if you opened the link I gave. It seems the budget in EU is particularly high.
I don't believe the optimal solution would be to move anything to IA: in fact, a separate legal entity would be much better option due to decreased legal risks. This only needs to be updated perhaps once or twice a decade, or even less.