However, you dont need to pay for it like that: Dismember allows you to pay for Phyrexian mana with 2 life for each Phyrexian mana, making a total of 4 life lost
In all likelihood, youll draw multiple cards if Archivist of Oghma sticks around for a few turn cycles
Recruit a trusted partner and fight shoulder-to-shoulder, hand-in-hand, or back-to-back for glory and the roar of the crowd
If this happens and the rest of the deck gets less expensive, Gaea's Cradle will be in for a big increase to fill in the gap
Furthermore, there are many more widely played formats (such as Tiny Leaders) I could provide a link to, but the reality is that if you include all those formats in your definition of previously banned, some person will eventually just invent a format that bans every card but basic lands, and therefore will be able to tutor all cards