Actually, TOS and TNG episodes suggest that 23rd and 24th cloaks work on different principles than the holographic camouflage I'm suggesting.
I'm curious - what in TOS or TNG suggests this?
Also, I may be splitting hairs, but an argument could be made that what I'm suggesting doesn't actually contradict Spock because the ships and mines aren't really invisible they're merely blending in with their surroundings.
But again the underlying problem is that Spock universally and categorically declares the inability to see the enemy ship a novelty. Techniques don't feature in this - only the end results do.
Which makes Spock's insistence all the odder, because camouflage is the oldest dirty trick in the book: a degree of invisibility should be an ever-present aspect of all combat, in the 23rd century just as much as in the 20th, the 8th, or the 24th. What Spock confronts in "Balance of Terror" is just a degree of invisibility anyway, as his sensors can still track the movements of the enemy ship. He seems strangely fixated on the relevance of perfect optical camouflage and the absence of such a thing from preceding history.
They never actually used the Bird of Prey cloak for anything useful in the show. The lines "a ship is approaching" and "they are moving off" could have sufficed for both incidence of use.
Agreed on this and the other arguments on "Minefield". But in the greater scope of things, invisibility should be quite familiar to space adventurers in all centuries: surely the older cultures would have invented it even in eras where the younger hero or villain cultures struggle with basic things like warp drive, shields or tractor beams. Saying that invisibility is new in the 2260s is, well, like saying that visual communications were only invented two weeks before "Where No Man Has Gone Before". Which is how "Balance of Terror" could also be read, although this probably wasn't the writer's intention at all.
Timo Saloniemi