Most families have some sources of post-death income besides life insurance. The most common source is Social Security survivors’ benefits.
Social Security survivors’ benefits can be substantial. For example, for a 35-year-old person who was earning a $36,000 salary at death, maximum Social Security survivors’ monthly income benefits for a spouse and two children under age 18 could be about $2,400 per month, and this amount would increase each year to match inflation. (It drops slightly when the survivors are a spouse and one child under 18, and stops completely when there are no children under 18. Also, the surviving spouse’s benefit would be reduced if he or she earns income over a certain limit.)
Many also have life insurance through an employer plan, and some from another affiliation, such as through an association they belong to or a credit card. If you have a vested pension benefit, it might have a death component. Although these sources might provide a lot of income, they rarely provide enough. And it probably isn’t wise to count on death benefits that are connected with a particular job, since you might die after switching to a different job, or while you are unemployed.