Multi-region is difficult and expensive, and a lot of projects aren't that important. Most of our infrastructure just isn't that vital; we'd rather take the occasional outage than spend the time and money implementing the sort of active-active multi-region infrastructure that a "correct" implementation would use. We took the recent 8 hour us-east-1 outage on the nose and have not reconsidered this plan. It was a calculated risk that we still believe we're on the right side of. Multi-AZ but single-region is a reasonable balance of cost, difficulty, and reliability for us.
I have some services which can cope with a 98.5% downtime, as long as they are available the specific 1.5% of the time we need them to run, as such "the cloud" is useless for that service
Right when you really want your thing to be up and can’t amortize hours of continuous downtime cloud has no solution for this. That’s something that often gets left out from the sales pitches tho =)
Depends on how critical they are to your stack. Ime if you use more than a few products and either one of them can take you down yeah it’s less than 3. Just something to ponder but if s3 didn’t meet 99.9 for the month you get a whopping 10% back. Other cloud vendors aren’t much better at this (actually worse). Not even to mention that you need to leave some room for your own fuckups