Earliest Christians who believed Jesus's body was gone did not see it as especially worthwhile evidence for Jesus's resurrection.1 (Scholars often make this point.)2 This is relevant because if they did not see it as especially worthwhile evidence, then they would not really be motivated to acquire an argument that makes use of it.
Robert Stein (citing Althaus) “...that if the story of the empty tomb arose as an apology for the resurrection, it is most strange that it does not serve this function in the accounts themselves (cf. Mk 16:8; Lk 24:22-24; Jn 20:11-15). [“Was the Tomb Really Empty?”, _Themelios _5.1 (1979): online] b) Early Christians felt that it was hard to establish the fact that Jesus's body was gone to persons outside Jerusalem. Wolfhart Pannenberg (Professor of Systematic Theology at Harvard [and others]): “In Jerusalem the empty tomb had to be important as a self-evident fact, but not equally so in Ephesus or Corinth.” [Systematic Theology (T & T Clark, 1988-1994), 359.] c) Early Christians felt that skeptics could explain it away relatively easy. For example, by saying…
• “…Jesus's body was simply stolen” (which, [since AD 30, is precisely what critical Jews were saying]),
• “…Jesus's body was simply moved elsewhere” (which was Mary's initial suspicion, see Jn 20:2, 13, 15).
• “…Jesus's body was simply assumed into heaven (like Elijah or Enoch).”
Even in the synoptic Gospel traditions where Jesus's missing body is explicitly reported, it simply did not function as apologetics/evidence for his resurrection. This is relevant because if early Christians desired to use the empty tomb as apologetics, then it would sooner play the role of evidence in the gospel traditions.
Early Christians who believed Jesus's grave was empty did not much use or emphasize it in their apologetics for Jesus's resurrection. This is relevant because if Christians really cared to use the empty grave as an apologetic for Jesus's resurrection, then we sooner would be seeing reports of it used as apologetics.