AWS/Google/Azure, if this happens, there should only be limited outage to a small fraction of customers. As a matter of fact, Google had such an incident before, and literally no customers (internal and external) noticed.
If you are using AWS, Google, or Azure, ran a single (or multiple machines) inside a single AZ with no backups and opted out of snapshots, you would face the exact same situation.
I can definitely say I see people complaining about how everything they have is down on AWS when us-east-1 goes down periodically, while large players that deploy sanely like Netflix fail over to another region seamlessly.
This [only owning a single machine at all] is what most of their customers whinging the most were doing. People that have actual sane production workloads on AWS or GCP are not going to be running 100% of their workload on a single EC2 instance with no backups.
People that are running on OVH are running often things like gameservers etc that monopolise 100% of a physical machine and don't support horizontal scaling. You quite literally cannot force a srcds/hlds server to "load balance" dynamically and fail over on heartbeat.
Often they are kids or students too, and the $30/m for a machine with 32-64GB ram is all they can afford (though this doesn't absolve them of paying $1-2/m more for offsite backups elsewhere)
You can provision more physical machines with the OVH API and have them be up in a different city in a minute or two. You get linespeed bandwidth between OVH DCs. It's up to you to use it.
The funniest tweets demanding their data and saying they'll lose everything are the people running:
https://twitter.com/Sensity_RP/status/1369496048998223873 - GTA5 multiplayer gameserver that begs for donations. Running on one of the cheaper sub-brands of OVH probably (soyoustart, for GAME ddos-protection). $30-40/machine.
https://twitter.com/pdfshift/status/1369550522479480833 - I can't tell if this is a troll
https://twitter.com/KatsanosAlex/status/1369501497348812801 - I can't tell if this is a troll
Or the button flips your DNS from your usual primary servers to a hot backup (or a cold backup that you brought online yourself).
And well, I guess this is one of the reasons.
As said earlier, their cloud service is unaffected.
e.g. I've got servers at OVH SBG-2, Hetzner's Falckenstein, and Online.net's AMS datacenters — the total of which is still almost a magnitude less than the same cost on AWS or GCP (granted, that's including traffic)
So, as a bare minimum, you rent at least two different machines at two different locations for each project and make offsite backups. It's still way less expensive than AWS.
If I don't need a powerful server and just need to spin some instances for testing or small projects, I use Hetzner Cloud, it's ridiculously cheap.
When you buy a storage API, sure, failure rates go up, latency increases 100x, but after a few hours its probably back to normal.
Of course, with the increased abstraction, you get more problems. "Availability zones" are useless when most cloud outages are because of configuration or systemic issues that tend to bring the whole thing down, no matter which AZ you are. But apparently it's now considered "good enough" to just go "oh we are down because AWS is down".
Yet somehow, at smaller providers and dedicated hosters bandwidth is usually included as a too-cheap-to-meter feature. Gotta love cloud innovation.
OVH has a lot of dedicated servers as well though, so if you're using one of those then it can't be moved very easily to avoid downtime.