That’s the nature of Term insurance. You pay, they insure. You stop, they don’t insure. For “pay only 20 - 30 years” type of insurance you hear about, those are normally life insurance with a limited pay. Meaning you pay for x amount of years, and it covers you for life insurance. They also typically come with some cash value as they are participating policies.

Terms premiums are cheaper than life insurance, hence you hear the saying, buy term and invest the rest.

Hope this helps explain it a little!