@jcf94 has explained very well for strassen algorithm. The link you posted is I wrote. However, we should notice that my post is not to show the best performance TVM could achieve, just show how easy TVM could a reasonable performance (beyond numpy).
If we still want to improve performance, we still could dig it. For example adding auto_unroll configuration / more split levels and so on. However, I think this is should be completed by our AutoTVM v2.0 (Auto Scheduler). You could try our auto scheduler. Simple matmul using topi should be upstreamed completely, right? cc @jcf94