As a casual gamer I find this aggravating. Why should the NPCs be left dumber and less human than they could be? It breaks immersion and makes the game harder for novices to enjoy.
As did I back in the day. But now I'm older with less time to micromanage pathfinding. And our devices are much faster than when many of these games launched
Well, in general, the rest of the answer to your question is that newer games tend to have better pathfinding, but adding better pathfinding to older games will make them essentially different games. Casual players might like it; serious players would throw a shit-fit. It's one of those "we can, but should we?" questions; everyone's going to have a different opinion.
Now...I don't see why they couldn't have included it as a toggle-able option. I know that I've considered trying to build updated versions of old games, and when thinking about how to do it, that seemed like the best choice.
When I heard these arguments and no rush or no attacking 20 minutes it would get under my skins. To me the T in RTS was Time and many people wanted to remove Time out of the game.
This is precisely why RTS as a genre pretty much died.
I thought it was pretty good, and more than enjoyable, when it came out 19 years ago.