Personal experience vs personal experience is kinda pointless, but there is typically a lot of CAS when I play 8.7-9.3. Albiet, a lot of them are ATGM helicopters, but that only furthers my point considering how good the Sgt York is at dealing with them, and how utterly useless Gepards (and weaker SPAAs) can be if the helicopter pilot is remotely skilled.
Outside of those, however, SAAB-105s and Alpha Jets are not uncommon, along with various weaker planes.
This means it can actually hit manuevering targets, something you’d be acutely aware of if you’d actually played a Gepard or Shilka. Even slight course corrections, if made frequently enough, will completely throw off the targetting solution and cause every shot to miss, even at ranges as low as a kilometer.
Since the Sgt York just needs to get close enough (Not to mention the tracerless shots mean aware CAS can’t see the shots incoming to jink them), planes can’t just trivialize them with basic awareness and manuevers. This means it can actually counter CAS, not just CAS pilots who are dumb enough to fly in straight lines and just hope that no SPAA exists.
Frankly, I don’t think you’re qualified to have this argument, since of all the SPAAs you’ve mentioned, you’ve only ever played the Sgt York, and you only managed a 0.4 KD against aircraft with it. Same with the M163 and Chapparal. If SPAAs at this tier are indeed so overpowered, how come you can’t make them work?