From the snaps it does seem to be the case. If you look closely not only have the minor patterns disappeared but the very small blocks linking the bigger blocks on the outer sides are very clearly visible in your case, whereas in the new tire these can be seen only at some depth. You may want to locate the tread depth markers. The little triangles usually found on the shoulders, the top tips of which indicate the usable depth of the treads. While diesel cars are known to consume tires at a faster rate than their petrol cousins, 10K does seem premature.