This is actually pretty hard to do. We all have heard of internet rot/dead internet theory.

One shout might be to link to internet archive instead of the resource directly. Though we can't be sure internet archive will keep the current system working as is (e.g. search params may change etc)

The only solid solution I have is to set up a foundation and pour money in so that they will be responsible for upkeep. But that would be an hassle to execute.

100 years in internet time is very long, internet as we know it now hasn't been along for 100 years.

I wonder if there aren't services that specialize in this.