Not necessarily true. I am
Not necessarily true. I am the original owner of a 2004 Prius. I currently have more than 193,000 miles on it and have had ZERO problems with the main battery. In fact it was in the dealer service dept last week for an unrelated issue - I asked them to test the main battery and they say it's absolutely fine.
Broad generalities are rarely true, something demonstrated by politicians daily. I also realize that one data point is not enough, so I will mention my brother's 2001 Prius which had more than 200,000 miles before the battery failed.