Harry Potter: 10 Majorly Dumb Plot Holes You Never Noticed
7. Time Develops Without Any Bearing On The Real World
What caused it: The films and their continued marketability.
It's not fully revealed in the books until the Deathly Hallows, but the entire teenage adventures of Harry Potter are set in the nineties; we discover in that book Harry's parents died in 1980. The other books alluded to this - Dudleys expensive technology and the new Prime Minister in book six (then 1997) - but it clearly wasn't something the filmmakers paid much attention to.
That alone isn't a plot hole, rather a disappointing element of the adaptation. However, in not grounding the movie series in a particular time it's meant the outside world development doesn't add up. Each film seems to be set in the year it was made, which is an understandable decision until you realise the characters age seven years in the space of ten.
Yes, it's being a little pernickety, but when you're finding plot holes in a fantasy series you have to be. It's a simple production decision that was never corrected and the series feels a little less unified for it.