I think it might be if things getting sold could have a more fair price, Mycelium can be bought for 700/block and sold for 125/block, maybe this could be bumped up to about 250 and give it a bit more of fair price to say that it requires a silk shovel, patience for it to grow, and a lot of dirt bought, to make it sustainable, I have a giant 63x63 farm and with that I only make a profit of around 100,000 per 5 real days. That farm is what allows me to be able to keep going on skyblock, without a decent profit margin my progress is really slow.
Perhaps some of the other types of blocks, like Brick blocks, stairs and sandstone blocks/stairs and clay could also become lower in price at 400-420/block its a bit hard to get anything done in game, in the W.I.P. shop concrete costs 10/block which is a better choice, for its look, integrity with building styles, and price.
Also I see the W.I.P shop has a few items, perhaps another item this place could start selling is enchanted books, the harder a different book is to get the more it could cost, like Fire aspect could cost 250/book while Silk Touch could cost 1000/book.
I know that the Economy must survive somehow, but the economy is already falling in skyblock with less players playing on it and things costing more than their /worth. Perhaps some could be changed and made to allow the game to be harder on that aspect, but make it so that rewards like price of Mycelium can go up to give players a goal to get to.
These are just a few suggestions, Thanks for your time.