Finally somebody nailed the problem. The power of allied tanks vs ost infantery is the key. It has nothing to do with tanks themselves. Just one sherman on the field is so much more horror to ost than p4 for the allies. I'd add that self repairing crews and capping are also a grat problem. Ost needs to retreat pios which means fewer squads on the field. Same for buidling which means that a lot of manpower can't be running on the field. Add this to free squads for teching and you have a huge imbalance in terms of decapping point and blobbing.
Oh the horror of one Panther negating my Sherman/T-34.