ambushes, useful or a waste of time and resources?

[Ludens]

Not to mention the people from Phocis...

Those too. I am afraid I couldn't remember any but the Thebans without looking it up .

Thespians not Thebans, the Thebans deserted and joined the Persians.

The Thebans at Thermopylae were from the anti-Persian party, I think.

I don't think that at all - I'm simply saying that it was the Spartans who were remembered because they were the SEALs, and the other guys were just Light Infantry.

I guess I am just tired of this hero-worship of the Spartans. They shared their most heroic feat with other hoplites (not light infantry), yet history has almost forgotten those.

[Tellos Athenaios]

The Thespians were there.

The Thebans were taken as hostages by Leonidas according to Herodotos, and did indeed put up a good fight while he was winning. However when the Greeks were finally surrounded they appear to have surrendered themselves to the Persians at once - claiming that they shouldn't be punished for their actions, because they were forced by the Spartans in the first place. While most of them got away scott free; the first rank(s) were killed before that message came across.