The truth is that most websites and services actually can be down for two days and still survive.
The culture of technology rightfully abhors downtime, and that's a good thing because it's our job to keep things up. But in reality there are very few companies who cannot survive 2 days of downtime. Sony Pictures is still in business, for example, despite an effective downtime of weeks.
Multi-day planned downtime for maintenance is even fairly common in Big Old Companies, especially for customer- and employee-facing systems. They just turn the thing off for a weekend, warn users in advance, and that's that. My bank's online banking seems to use that strategy. A few times a year, it tells me: sorry, but due to planned maintenance you'll have to check back Sunday evening. It's kind of surprising to me every time, but seems to be common. Some big companies do it with employee infrastructure like corporate email or network drives too. Some kind of system migration (or even physical server move) will mean on a random Saturday there's no email or file access. Announced in advance, sure, but it's still down for the day.
Verizon telling you that some random servers are going to be down for two days admittedly might be worse than taking one of your own systems down for a maintenance window is, especially if you didn't expect in advance that such a thing was going to be a possibility, and made the mistake of putting really-can't-be-down stuff on Verizon's cloud.
Doing a rollout for a Fortune 100 company pretty soon and they built in an outage of a few hours. And it's literally because they won't spring for 1 extra server running apache even with 6 months lead time.
downtime costs money; frequently, a LOT of money. it's not a question of survival. severe downtime losses should be compensated, this is why SLAs exist. i can't put my team on involuntary furlough, citing shitty infrastructure choices.
The culture of technology rightfully abhors downtime, and that's a good thing because it's our job to keep things up. But in reality there are very few companies who cannot survive 2 days of downtime. Sony Pictures is still in business, for example, despite an effective downtime of weeks.