And for all we know, the Romulan cloak in TOS and TNG is based on the very same principle, and none other exists in the Trek universe - save for the phase cloak, which is the one and only innovation in the field, and justly revered for this.
This doesn't explain why Spock would remain ignorant of Xyrillian and Romulan invisibility as late as the 2260s - never mind Suliban invisibility, a technology Starfleet itself exploited to notable tactical gain. Sure, invisibility might be a major military secret, and its use generally so limited that civilians need not learn of it. Starfleet thus might practice self-censorship and only inform certain key officers of this technology and its past uses. But nothing in TOS or other Trek makes this particularly likely; invisibility is quite commonplace there, and likely to be encountered by all sorts of spacefarers.
Actually, TOS and TNG episodes suggest that 23rd and 24th cloaks work on different principles than the holographic camouflage I'm suggesting. 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. Also, Section 31 probably hid the info on the Suliban cloaking info and possibly covered up all info on the Temporal Cold War potentially explaining why Daniels said certain things weren't supposed to happen yet they were not reversed.