They do have to weight that against the very real possibility of many, if not most, of the players from server you merge with end up quitting as a result. Not only does that mean potentially losing a number of lesser spenders, but it also means that you are back where you started, in a dead-ish server. There are a number of already merged server requesting merge again due to the server dying again for whatever reason, and high ptw could very well be such a reason.

It's hardly any particular parties' fault, but that is the nature of such ptw games. I wonder if things would be better if the huge spenders promises to not plunder as well as make certain compromises in GNW. While not exactly fair for the spender, it would certainly minimize the impact and thus allow the merged server to sustain longer.