That's what Modern format is good for

The main purpose of Modern Format was to give Splinterlands an affordable entry price to new players. With the amount of printing and older cards out there, literally 100% of the use case is taken away with Wild format where you are forced to run a bot, and the costs to enter barely get covered by the earnings. It has become impossible to still have fun with older owned cards.

The main reason they are sticking to making new cards is because there is still a group of players left who will buy them even though this group is clearly shrinking as shown by Rebellion. Also, how does it makes sense to sell more cards to mainly cover the cost of the creation of the new cards.

The only thing that matters to bring in new players are green candles and the belief of new players that their card assets will hold up or increase in price.