Why term is so much cheaper
Term insurance only pays out if you die during the term, and most people outlive a 20- or 30-year term, so insurers can price it low. Whole life is built to pay out eventually, plus fund a savings account and commissions, so premiums can be 5 to 15 times higher for the same payout. For a young family, that difference is the gap between being properly covered and being underinsured.
'Buy term and invest the difference'
The savings inside whole life usually grow slowly after fees, often well below what a low-cost index fund has returned over long periods. So the common advice is simple: buy a large term policy for cheap, and invest the premium difference yourself in tax-advantaged accounts. Over 20 to 30 years, the invested difference usually beats the policy's savings, and you keep full control and easy access to your money.
When whole life genuinely makes sense
Permanent insurance has real uses: covering estate taxes so heirs don't have to sell assets in a hurry, providing for a dependent who will need support for life (for example a disabled child), funding a business handover, or a high earner who has already maxed every other tax-advantaged account and wants more tax-deferred growth. These are the exceptions, not the default a salesperson may present it as.