Absolutely false. An obvious counterexample is that the "victims of the Sept. 11, 2001 terrorist attacks received more than $38 billion in compensation"[1], even though, as of 2015, "40% of those who died are unidentified".[2]
The article itself gives a counterexample: "In 2002, a British man named John Darwin “disappeared” in a canoeing accident only to be discovered five years later with his wife in Panama. Apparently, she’d cashed his life insurance policy to pay off their mortgage."
And if it were true, insurance companies would simply say, "no body, so payment denied". They wouldn't rush to hire a skip tracer as the article claims: "remains don’t turn up within a few weeks of their disappearance, that’s when insurance companies start blowing up his phone".
The article is very muddled on this point.
[1] https://www.latimes.com/la-110804compensation_lat-story.html
[2] https://www.theguardian.com/us-news/2017/aug/08/remains-911-...