There usually are rules that require "delayed settlement ineterest" be paid, sometimes at a high penalty rate -- after a set period -- often 30 days from filing a claim, although some comapnies pay interest at their earned rate from date of dealth on all claims.
If the policy was idividual insurance in force less than 2 years, it is still contestable so the companies investigate. Same is true if there is a qustion as to the accidental nature of the death and the policy has a"double indemnity" provision, or if was an accidental death benefit policy, or if the beneficiary is suspected of complicitity in the deceased's death, or there are multiple claims.
If a company takes far too long to pay -- and that would be far more than 30-45 days from the receipt of the proof of death -- it may be evidence of "bad faith", especially if there is a pattern.
The state insurance department can also answer your questions.