They cost no mana to play but a player may play no more than one land per turn, and only during the main phases of their own turn
Marchesa, the Black Rose is certainly an excellent card, and Silence has its place in cEDH, but its basically a grouping of sub-par/good cards that players either already have, dont really need, or already had access to for a couple of bucks if they really did want them
This sort of interaction was enough to earn Hullbreacher and Leovold, Emissary of Trest spots on the Commander ban list
While there are several other versions of Elspeth I'd probably be keener to put in a Trostani deck, the original Elspeth Tirel at least makes sense
Yes, we have access to Duals and Moxes, some Elves and Mana Birds, Initiates/Priests (outside of Sweden, at least), and a Prism that Ive never seen anyone play, but once you add in Factories, a Strip Mine or four, Maze, Library, youre suddenly running 25+ lands