On my home network I use Google as a backup DNS provider so the whole internet didn't go dark for me, but I don't have a backup DNS host for my company's DNS records.
This is a very common pattern and falls into the 'nobody got fired for buying cisco/microsoft/intel' trap.
I have two issues with it;
1) It entrenches the largest provider.
You would not extend the same leniency's of outages to the third best cloud provider, this means that people will just keep pushing the monopoly forward. Even if the uptime or service is actually better on another provider.
2) You create a tight coupling of monocultures;
Simply put: You slowly erode the internet. Your site becomes an application in a distributed mainframe operated by a tiny minority of tech companies universally based in the US.
Why is this a problem? I could give moral answers here but I thing pragmatic ones are more convincing..
Giving ownership of the internet to the few gives them the ability to set the rules.
If you're on Amazon's AWS, what's to say they don't inspect your e-commerce systems and incorporate your business logic into their amazon.com shopping experience. They do this to their marketplace and create competing products already[0].
If you're doing really well, why not just drop a few packets here and there? I mean, they wont.. you're paying, right?
Hell, if you do super well they can just change the rules and make it so your services get expensive in the exact way you use them, or even legislate you off the platform entirely.
Probably wont happen, but it's a lot of trust you have to admit, and people shit on Apple for having that kind of power, and Apple is not even competing in the same market as most people on this site.
If you're on google cloud (which, I'm a fan of btw) and you feed an ML model, well, you paid for it but why shouldn't they also have a copy.. after all, it's green to do so! Their bigdata platform? Google loves data! Feed the beast.
[0]: https://fortune.com/2016/04/20/amazon-copies-merchants/
Amazon can copy your business model just fine without looking at your servers. Most of what’s on your servers is probably irrelevant from their perspective.
The original idea was that with the barrier to entry being so low, anyone and everyone could set up their own websites, mail servers, etc.
But with it being so easy to compare and contrast service (i.e. the market being so open), it means that the competitive forces naturally consolidate to a winner-take-all model. If when starting out Cloudflare was just 5% better than the competition, it could have easily taken the vast majority of the mindshare on the internet. Couple that with the fact that there are huge advantages with scale to a business like Cloudflare's, and it's not hard to see how so much of the internet has become dependent on it.
We REALLY need a truly decentralized, distributed DNS system that is not owned by private entities.
https://ieeexplore.ieee.org/document/7530014/authors#authors
> Unlike previous DNS replacement proposals, D 3 NS is reverse compatible with DNS and allows for incremental implementation within the current system.
You can also also register your domain on multiple TLDs.
I know a lot of big companies do, but I am always surprised when you see ones that don't.