It looks like we're still on track to hit higher lows, maybe you should zoom out.

And really now, how can devs prevent a whale from manipulating price 

You need to keep in mind this coin uses a scientific PoW, in that regard it's doing very well, it's merely a geeky prime number coin. This is why you see most contributions to the project are around improvements in mining.

That being said, having more average people mining the coin would help create a more even distribution of new coins and reduce some of the whale manipulation we're seeing.