Is it too late to expect an ROI?

I originally wanted to mine 8 months ago but chickened out due to the uncertainty behind PoS timing.

Now with the looming difficulty bomb, I'm wondering what your thoughts are on a potential ROI if I built a few rigs now.

I plan on only selling enough ETH to cover electricity costs ($0.12 USD/kwhr) and storing the rest as an investment. Should I give up on my dreams of mining and just buy ETH instead?

Thanks for your input.