17 ISPs trunk straight to the open internet and I take 2 links off that open internet and have them redundant going to the one wire to the rack.
Any one of the 17 fibers can get cut and it's fine. Any one of the redundant links can go down and everything is fine, if someone cuts my physical link we are hard down (this is good and bad, as I can also disconnect from the internet simply with one cable)
The 17 ISPs contract with the colocation provider and its a mutually beneficial thing. They can sell capacity for them downstream and it also gets them a place to get out to the open internet backbone. These are exclusive to tier 4 facilities typically.
Basically Surly isnt going down for you unless your DNS server is blacklisting us (Verizon for a hot second did this) or I fuck something up.
We had one network outage that lasted ~90 minuted a few years ago that was a huge deal, but I failed out into azure because ive got DR set up outside and did that via DNS update.