There is a fundamental difference between reliability and longevity.
Longevity does NOT equal reliability. Something that works 10 out of 10 days is 100 % reliable. However, it is short-lived if it dies on the 11th day.
SSD write-cycle exhaustion is not the issue like some here would assert. Heavy use isn't going to kill SSDs at a rate that makes them less reliable than HDDs. It's a fallacy from the days of old that is perpetuated by those that don't know what they're talking about.
And you're not even comparing apples to apples because the reliability indicators for SSDs and HDDs are different by their very nature. So there is some subjective assessment that is made because the absolute numbers don't tell the whole story. However, the narrative that is widely spouted is that "HDDs are more reliable than SSDs." And a lot of people unfortunately have that burnt into the inside of their skulls. It's poppycock, not only from a technical perspective, but one based in reality and actual study after study.
The primary driving factor behind continued heavy HDD use instead of SSDs is money, and not reliability. The install-base of HDDs is huge, and companies aren't going to needlessly spend money to switch-out existing functional hardware. They'll use it until it dies. (Why many still use XP.)
One buys and implements hardware based upon the premise of a balance between desired workload, performance and cost. What is the single biggest determinant of virtually all things human ? - money, of course. So why am I going to spend $1000 on an enterprise SSD when I can buy an HDD for $100 that will meet my workload requirements ?
Nowadays the reliability of SSDs is every bit that of HDDs. In fact, in the harshest of environments, SSD reliability exceeds that of HDDs.