There is a limit to how much life insurance you can buy, and the way it is determined is called financial underwriting. At each age, the insurance company will set a maximum amount of coverage that can be purchased at each income level. E.g. At age 30 they might allow 25 times the annual salary. If your salary is $60,000 per year, you can get $1,500,000.
However, underwriters also consider assets and liabilities, as well as other income in the household. So it can be possible to get far more coverage than the income formula allows.
The purchase of life insurance is predicated on financial justification to come up with a death benefit. If the justification amount can be certified the death benefit, the numbers can become quite large, over $100,000,000. Many large insurance companies offer jumbo limits to 65 million. You can also justify life insurance coverage with the expected earnings (human value) for an individual to age 65 and use a multiplier to increase the death benefit amount.
However, underwriters also consider assets and liabilities, as well as other income in the household. So it can be possible to get far more coverage than the income formula allows.