Yeah, it's kind of ridiculous. One more wasted opportunity to make something legendary with this franchise.
That's the problem in this day and age, practically every developer out there is so strict on the cost-benefit analyses that absolutely nothing can ever be better than "sort of good", because anything beyond that is too expensive in terms of resources relative to the marginal benefit.
Will a time system and day/night cycles add complexity and cost more resources? Yes. Will it sell more copies? Probably not that many. Right, idea rejected. Let's just go with weird static time that leads to eternal noon everywhere. Everybody will love that, right? And never mind that BG1 had a time system with day/night cycles well over 20 years ago.