I’d say it’s a bit of both. While the core principles remain the same, there have been some significant advancements in manufacturing, materials and user interfaces. Those little improvements really do add up over time.
Here's something you might not agree with: I think duty pistols were at their best years ago. The new ones mostly just change the grip, have different optic cuts and sound cool in ads. The actual reliability and how accurate they are hasn't changed that much compared to guns from the early 2000s.