I think they choose "Enterprise"-grade SSDs to have a run temp of 55C.
I don't know of an HDD enterprise environment like that, but I haven't worked with
any off-the-shelf SSD enclosures in an enterprise, so I don't know why they'd choose such
a high run temp.
In server rooms I work in the intake air temp available is around 18C.
There's been a trend recently to up the temp in data centers to save power and be more "green". I know we upped ours from something like 65 to 70F and didn't notice any more failures. Due to an AC failure one part of the DC got up to 90F with little long term effect. Server fans spun up and there was some throttling but everything survived fine. Amazing what abuse this stuff will take.