The Zaskar was a good bike. In 1996. When 26x1.95 was the typical tire size and 80mm was a long-travel fork. Long-and-low was what worked on the NORBA style courses of the day, biased towards climbing and speed on the flats. When you look at rider position, it’s not that far off of a ‘sporting’ road bike of the same era.

Modern MTBs have bigger wheels, longer travel suspension (with much better dampers) and the geometry and rider position to take advantage of that. I’ve demoed a couple of new mid-range trail bikes in the last year, and their off-road capability just blows away my old F-1000.
Now, on a fast fire road, or on slicks in the city, the old XC bike probably has the speed advantage, but that’s what it was designed to do.