What's the last Roman history you've read? I must admit I have been rather lax and lazy this past year since I've gotten my Masters, but I did read through "Visual Evidence for Roman Infantry Tactics" A week ago. Here, have a full citation:
Taylor, Michael J. “VISUAL EVIDENCE FOR ROMAN INFANTRY TACTICS.”
Memoirs of the American Academy in Rome 59/60 (2014): 103–20.
www.jstor.org/stable/44981974.
Feel free to read it yourself. I didn't find myself fully convinced to be honest, but it was an interesting read. It's a bit heady though, involving the examination of artistic reliefs, epigraphs, and other such works of art, which is a bit in the weeds if you aren't already sort of well educated on the base subject. It assumes familiarity with textual analysis.
I'm afraid I'm unable to let go the thing about Greek hoplites not fighting in formation. If it really is true, as you say, then you need to explain it properly, given the sheer mass of evidence to the contrary.
You say that there is no evidence that any non-Spartan cities engaged in any kind of hoplite drill. That is an enormous claim. Are we to understand that, in the dangerous and violent ancient world, some states put no effort whatsoever into military training? It seems far more likely that, through things like the
gymnasia of Athens and the
Campus Martius of Rome, Hellenic city states had organised civic military training.
You say that the Spartans marched to music in formation, which other armies didn't. But that is slightly disingenous; it makes it sound as if marching in formation was part of what made the Spartans distinct, when in fact it was that they marched silently to music.
It is certain that, by the Battle of Leuctra in 371 BC, non-Spartans were fighting in phalanxes. This is certain because the Theban tactic of drawing their hoplites up in much deeper formations than normal would not make sense unless fighting in formation was not already the norm.
It also seems highly doubtful that the non-Spartan soldiers at Thermopylae in 480 BC did not fight in phalanx formation. If they had fought in loose order, the battle would have been over far more quickly than it was.
So when exactly, in your understanding of all this, did non-Spartan cities decide to stop throwing hundreds of lives away fighting suicidally without formations? Come to think of it, when exactly did the Spartans decide to do it?
Is it possible that, when you say that no Greeks other than the Spartans fought in a phalanx, what you actually mean is that the Spartans were much better at it than everyone else? I do find this all very confusing; the enormity of the claims you make is in striking contrast to how casually and brusquely you make them.