I never bought pet insurance. It only seems to be in the last half a dozen years that there's been a widespread sales push for it but my two mogs were already old by the time I took notice and, anticipated rather than proven, I didn't want to waste the cost of a phone call to find out that it would be high premiums and significant exclusions.
One of them had an overnight stay for tests, a terminal diagnosis and PTS at age 18. This worked out at about £2/month over her lifetime. (ie over £400)
If you don't have the resources at the outset or think you lack the discipline required to not raid the savings pot, then pet insurance is for you.
If I got a puppy/kitten now, I think I would go for insurance.
Following on from what mcfluff said, ring around, ask about exclusion clauses first and make out that this is more important to your choice than price. If enough people do that, they may catch on to what customers actually want.