When you purchase a server (fleet), you get a long warranty with it. Generally 3 to 5 years. So you expect this fleet to stay in service for <=5 years mostly.
Unless you burn through your SSDs, you're very unlikely to hit this event.
When these servers' continue to be used and disks all start to fail at the same time, this will obviously stink.
The bathtub curve is not like this. You can feel that.
40k hours is a little more than 4.5 years. These drives deterministically fail at that uptime (unless firmware is updated) and most servers are on 24x7, so if you run your servers for 5 years, it's highly likely you'd run into this. If you run your SSDs hard and they fail early as a result, then you'd be spared from this mass death. Or if you use three year leases and replace on a schedule.
Now more than ever, five year old server hardware isn't that far behind the curve unless you're on the bleeding edge. I've been looking for bottom of the barrel hosting lately, and there's lots of dedicated servers available with 10+ year old cpus, and probably most of the rest of the machine is a similar age.
I haven't used them yet, but take a look at dedicated server offers at LowEndTalk and Web Hosting Talk. Obviously, there's some offers that are sketchier than others, and a lot of resale, but if your needs are low, there's some neat stuff.
Unless you burn through your SSDs, you're very unlikely to hit this event.
When these servers' continue to be used and disks all start to fail at the same time, this will obviously stink.
The bathtub curve is not like this. You can feel that.