They must be.
Probably the insurance company has figured that ART is a pretty profitable business for them. First, they get to price it annually so they can incorporate mortality risk appropriately and easily. Second, and less obvious, as the price of the insurance rises over time due to mortality risk and their customers realize that they are more self-insured and don't need the insurance and it is becoming less affordable, the customers cancel the product, saving the insurer the $500K or $1M or whatever payout they were on the hook for, so all of those premiums, minus some commissions and paperwork costs, are pure profit.
You didn't ask, but what I did was buy vanilla level term insurance for either 10 or 20 years so I had my price locked in. I then saved like mad so I could self insure as early as possible and drop the term insurance coverage. Lots of online comparison companies, and the premiums were autodeducted from a checking account. Make sure you pick an issuer who you trust to be financially sound so they can pay in the very unlikely event that you end up dying during the term.