My petplan covered for life hasn't gone up 500% since we started the plans 12 and 9 years ago.
The price doesn't go up for claiming either, it goes up each year regardless but not 500%.
Good timing actually, our doggo's renewal is up so been shopping around yesterday, just for curiosity on one of the more competitive quotes I checked what it would be if she was 13 rather than 3 (everything else on the policy the same).
3 year old: £32/month
13 year old: £308/month!
That's almost 1000% increase, and in reality it would almost certainly be more after the 10 years due to inflation.
Granted that's only from a sample of a single insurer, but at that point, surely for most people it would be a case of saying **** it, and deciding to take the risk and "self-insure"