dOUBLING IS OK BUT THAT PREDICTION OVER THERE ON THAT LINK (damn caps lock) expects some 16 times harder difficulty in a time asics made from chips will start working. If that happens, that investing won't meet roi soon if ever.
Not sure how you got that from his table. I see 4x increase by July 19th, almost 3 months from now. Which is close to what I expected when I went ahead.
But there are many variables and any option is a gamble and always has been. I expected to shut down my GPUs last November but delays in ASICs and bitcoin price increases rather surprisingly has made GPU mining more profitable now than even 2 years ago. So, just never say never. As long as people aren't thinking difficulty will drop or doesn't matter they have their own choices to make regarding the future.