I think web users have lower expectations than Ye Olde Worlde desktop apps. They are used to pressing F5 to refresh if stuff doesn't seem to have worked.
If you get your cloud architecture right then recoverability is more important than 100% uptime. For example, the user clicks buy.
The event message goes onto a distributed queue with at-least-once delivery. If the DB is down then the data is in the resilient distributed queue until the DB is back online and can drain the queue.
There is much heavier use of caching components that also take the pressure off the database. Where as an old app might query the DB directly for the product catalogue a web app might get the images from a CDN and the product data from a cache, only falling back to the DB when the cache has expired. From the customer perspective they get the product info whether it is from the cache or the DB. There will be a difference in performance but maybe not noticeable to the customer.
In retrospect I think in many cases the 100% uptime requirement was as much badge of honour and personal pride more than it was pure business need. The cloud presents a thing you consume rather than control. As soon as you are not in control then you need a new badge of honour.