Pythons are the most expensive PRODUCTION revolvers in the world.
This is because the 100 year old Colt action is an intricate mechanism that requires
extensive hand fitting to build. The Python receives even more hand polishing and tuning which costs a considerable amount of money.
The external Python finish requires the services of a master polisher with years and years of experience. The Python was polished to a level of finish no other production gun ever approached. Again this cost money.
The Anaconda is a derivative of the Colt Trooper Mark 3 of 1969. These newer Colt guns are designed to use much less hand fitting during factory assembly, and this costs less money.
The later Colt guns like the Anaconda simply weren't polished to anywhere near the same level of finish.
So, less internal and external finishing, and a simpler action design that required little hand fitting, makes for a cheaper gun.
Since there were fewer Colt .45 Anacondas made than the more popular .44 Magnum, the .45's usually sell for more.
When the .45 Colt was in production, the price was the same as the .44 Magnum.