There are many things that could be happening, but in essence, what I have found is that TT or any other ceramic needs to be handled more carefully than the way they are described as "work horses in my kitchen" by Tara on air.
Some things that can shorten the life of stoneware are
Soaking in water. Not a good thing. The unglazed areas will absorb water and lead to crazing and cracking.
Dishwasher are hard on dishes. Period. Very high temps, lots of water. I don't have one, but have seen repeatedly how hard they are on dishes, glasses, and flatware.
Stoneware can't be banged and bumped, or it will chip or weaken the glazing if not done properly. The unfinished bottoms scratch the other pieces when stacking.
There are varying qualities of stoneware, even among the 'made in China' brands. Some are better than others. Temp-tations dinnerware in particular (as opposed to some of the baking pieces) have not held up well for me. I've thrown out many pieces from crazing, but haven't had problems with chipping unless I really banged them against something. The quality just isn't there.
In all fairness, I have some made in America brands that have had this happen over the years too.
And getting the pieces replaced costs a $10 shipping fee. I have decided when mine are gone (I have had them since first introduced) there will be no more of TT dinnerware for me. I will use them until I no longer have enough to make a set, and I will donate the remaining pieces and move on.