Definitely not over, heaps of places improvement can be made. Upper can go down to 14:10, less even. Not sure about MoS, but only 2 big dog teams have hit MoS hard so far.
And that nelth is 25seconds less with no healer, could definitely lower that time with some good rng and practice. It's very likely they had deaths they could prevent.
You might be overestimating the amount of time people have put in so far, or how much they put into 1 dungeon before moving to the next.
Like where's Methods MoS time? Where's that chinese groups Upper time? Wheres Asmons groups Nelths/Fully farmed MoS time? And others.
They aren't there because there's only so much time available. We're 4 days in. It's not 1 dungeon a day for 8hrs and you're done. They can easily drop 2-3 8hr+ days into a single dungeon, and keep improving the time.
Also, A lot of these guys still work. There's only so much time they can put in during the weekdays. Should see more changes than just that Nelth over the weekend.