That would be too easy, Laser. It would also make NM DLs, Caras, and almost all challenging raids useless because everyone would pick the rare drops and take full relics/stones.
Another thing, in case you don't notice, because I didn't, you can up the speed in how fast the turtles come out of the pipes at the bottom of the shop, which with all at level 150 got me to 50k in under 10 seconds
I made a thing with the saws that flings the turtles to another saw and back and forth, so once the turtles get stuck in there, they can't get out. got to 30k with that in less than 2 minutes
Also forgot to mention that they offer 1000 PC to you for 15. Granted you may have to buy it a lot, but that's over $100 lost every time someone gets it.
Really, there shouldn't be any Gold to PC in this game. After buying King's a few times, you get 150 PC per time, you get 20 PC per 100 levels, you get PC ever 2/4/6 weeks from idols, and if you play long enough, you'll get 500 PC at level 2500