Just imagine if the Captain was incapacitated, at night, over the middle of the Pacific
Forget the other scary stuff included in that comment. An incapacitated captain is bad enough. Recently the subject came up during a conversation with the chief pilot of a Boeing 737 operator. His advertisement for first officers included specific minimum hours prior to interview. These limitations were dictated by insurance premiums.
At the same time there are well regarded SE Asian airlines flying heavy metal with hundreds of passengers aboard and whose first officers (second in command) may have only 100 hours or less, total real command time in their log books (none of this PICUS rubbish) along with 3-500 hours TT. No problems with insurance minimums with those operators.
Captains don't have heart attacks in flight very often. Thus, statistically the chances of the low hour second in command assuming control over the Pacific at night with all the other frightening variables, is so low as to be negligible. Insurance companies probably take that into account in setting premiums. That said, there is little doubt that many captains with very low experience first officers foisted upon them are quietly uneasy and would prefer someone in the right hand seat with extensive decision making time in their log book.