I think OP meant to compare a known hard task vs an unknown hard task. Both are hard, but first is known to be possible to finish, but the other not so.

A widely accepted method fur judging at least subjective risk when there are insufficient facts for truly objective measure is to ask how much you would bet on various outcomes - such as whether P=NP is solved before New York's 2nd. Ave. subway is completed.

So, in a sense I think that part captures the problem. People object to testing backups using the logic of "with our shitty processes, it will be dangerous". I suppose you have companies with a logic akin to "due to being cheap arrogant, we have shitty processes" -> "due to shitty processes, our processes are fragile" -> "due to being fragile, we avoid anything that would stress our system" -> "due our system not being able to take stress, we just pay ransomware instead of stressing system with a backup".

It seems like we've reached to "throw-away enterprise" level. Build it cheap until it breaks, then walk away when the fix cost is too high. There's a cost-benefit to this. Reminds me of bandcamp and other declining sites that just vanished one day with information some would consider valuable.