So I looked through the epic shop and once you have the fairy castle that produces stalks at some point there is nothing left to buy.
I did see a suggestion to make the FT castle also give population (not per hour but a flat amount), but why not add some nice things from the gemshop to it. Like allow people to buy a single Endless Coppermine for beanstalks. Set it at 20K and they have something to save up for.
Basically increase the things you can buy with beanstalks to make the FT castle interesting again. You could even rotate it as with the guildsection in the shop.