IOW, you're comparing a hybrid automobile to a flashlight and assuming batteries will need frequent replacement.
As I said, Sweetie's Prius was 12 years old (and is still being used by her grandson, making it almost 14 years old now) and has never had a problem with the battery (except the one in her key fob), much less needing a replacement. Linda's Prius has now gone more than 10 years with no battery issues. Both cars have been used in a way that's least advantageous to battery longevity: i.e., sitting unused for days at a time and lots of short trip driving.
Not one other person I know personally has had any battery issues and ownership length has been between 3 and eight years now. Toyotas have been known to run without any battery issues for up to as many as 250,000 miles, which is impressive for any car! There are numerous instances where the battery has lasted about 350,000 miles.
These numbers in both years and mileage compare well, and are perhaps even better than, ICE transmissions and many ICE engines. See the example below.
I miss my ‘67 Ford Fairlane Jack Webb special.
bobistheoilguy.com
We can both throw numbers around and point out outliers for both systems but in reality, the hybrid batteries on many models will generally outlast engines and transmissions on many ICE vehicles, just as some batteries will not last as long due mostly to poor or improper maintenance. They've been around a long time and they are no longer new, unproven technology. Treat 'em right and they'll last.