The rental market always has been a massive hassle and the only way to manage it is by using a bot service which takes away part of the earnings and with the 1 DEC listing price that also became impossible. In the end players aren't going to pay more than what they earn for rentals.

Unless card prices are high because there is limited supply and high demand, rentals aren't really going to make a comeback. One of the ideas of investing in cards has always been that it would be possible to just keep them as assets and just put them to work. However, flooding the market with an insane amount of cards while making old cards useless in Wild killed that idea.

The only way I see rentals working properly is with a game mode that has an entry fee and where players who delegate cards for it get part of the earnings. That way it's 1-click easy for those who want to rent out cards and those who are renting don't even have to do anything as it's all included in the entry price.