Why isn’t the upper bound on block timestamps (+2h) set by the consensus rule?

Why isn’t the +2h acceptance rule part of the agreement? Of course it can’t be based on network coordination time + 2 hours. This is because in extreme cases one part of the network may accept something and another part may have to wait a bit, but why it is not set, for example, the lower bound remains the same (the median of the last 11 blocks) and the upper bound remains the same (median of the last 11 blocks). Based on the value, it becomes +2h. This way the entire network has the same value.

Why didn’t you do this? What problems will arise if implemented like this? What is the problem?