There are several reasons for this and they have historically spanned all iterations of aggressive blue decks
The median asking price was Rs3,500
It's still a great card that might pick up value as Celebrations' original release date gets further away, so now is probably a good time to grab one if you've been waiting.
These include Urza's Power Plant, Urza's Mine, card Urza's Tower, as well as the newer Urza's Saga, Urza's Workshop, and Urza's Cave
I wouldnt go overboard with adding extra ramp either because the curve is quite low and there are plenty one, two and three drops to the point more ramp can kind of feel like a dead draw
Without mana ramp, youre restricted to playing one land per turn