Inotera (which produces about 1/3rd of MUs DRAM) is also node transitioning to 20nm. Samsung has been through this song and dance before. The only thing additional capacity will do is force the other guys to also ramp up capex and do note transition to 20nm quicker. This strategy worked when you were in an era of 10 players, or 6 or 5 or even 4 with Elpida having a weak balance sheet. The only reason it would make sense for Samsung to be aggressive if it felt it could kill one of SK Hynix or MU (as they won't be able to keep up) and at the moment that seems next to impossible. The remaining guys are all very strong with robust balance sheets and technological strengths SK Hynix is a $45b mkt company and MU is a $33b mkt company and both have ample access to equity and credit markets. These guys will not go away and will respond to capex in kind. So game theory now dictates that the best strategy for profit maximization is not try for further consolidation or mkt share gain. So since you can't kill them then it's finally time to take the foot off the pedal (which Samsung has had on since 2000) and after decades of consolidation finally enjoy the fruits of that labour. You could try and kill Nanya with the little capacity it has left but it's so small that who cares. And Inotera is just a MU subsidiary pretty much.
The other major step change driving the change in thought process is that Samsung is vertically intergrated and its major competitor Apple is not. So any decrease in DRAM prices not only dispropotionately hurt Samsung but also dispropotionately benefits Apple as well as the hundreds of white-box manufacturers. All these Chinese players willing to sell phones at 0% or even negative gross margin, only hurts Samsung more if they can price the phones even lower since DRAM prices is lower.
So to summarize, you can't kill the last 2 players, if you ramp up capex so will they and noone wins, and meanwhile any depressed pricing only benefits all your competitors in your other businesses (and handset sales was 2/3rd of Samsung revenues). It makes no sense for Samsung to be ramping up capacity too aggressively.