the real problem with this run of luck - now effectively over 350% for the current block soon after the two monsters - is that as a business right now the only way to run is to reinvest profits in additional equipment, as that's what everyone else is doing, driving the difficulty increases (and, one would think, the price appreciation). When there are no profits (or significantly reduced ones) to reinvest, you lose ground to the pack.

Side note - this cycle: price goes up, everyone re/invests, difficulty increases, repeat, is extremely worrying and at some point really does begin to look ponzi-like.