In fact I used to run some hobby projects in OVH (as an aside, I really liked their services) so I’m aware that they have their own failures too.

Colo space assumes that the colo is operating more efficiently than AWS/Azure/GCP when in reality you’re comparing apples and oranges.

    financial services, telecom and high-precision manufacturing companies

What use does a CNC shop have for an extensive on-prem multi-DC with failover and high availability? It'd be like buying your own snowplows to make sure that the road is clear so your employees can get to work. Maybe necessary if you live in a place with very bad snowplows and no existing infrastructure, but in most places, just a waste of money.

Also the reasons those companies usually run their own infra is historically down to legislation more than preference. At least that’s been the case with almost all of the companies I’ve built on prem HA systems for.

Also buying fuel for a petrol station is going to be more expensive than having a commercial tanker refill it. So ideally you wouldn’t be making large top ups from the local petrol station except under exceptional outages.

As for wider power outages affecting the fuel pumps, I suspect they might have their own generators too. But even if they don’t, outages can still be localised (eg road works accidentally cutting through the mains for that street - I’ve had that happen before too). So there’s still a benefit in having a petrol station near by.

To be clear, I’m not suggesting those petrol stations should be 5 minutes walking distance. Just close enough to drive there and back in under half an hour.

some natural disasters can render driving trickier than walking. extremely large snow storms, for instance. you can still walk a block, but you might be hard pressed to drive 5 miles.

(i don't have a bone in this particular cautiousness-fight; personally i'd just suggest folks producing DR plans cover the relevant natural disasters for the area they live in, while balancing management desires, and a realistic assessment of their own willingness to come to work to execute a DR plan during a natural disaster.)

Then you’re not running HA and thus the argument about cloud downtime being “worse” than on prem is moot.

Obviously if your SLA is basically “we will do our best” then there are all sorts of short cuts one can take. ;)

I’ve never seen a data center with natural gas backup power. But I don't know if that's because of reliability or if it's too expensive for a big natural gas hookup that's used rarely. Though I have heard of the opposite -- using natural gas turbines as primary power and utility power as backup.