To answer the OP’s question, there are a number of possibilities. I can only speculate.
The biggest reason for ATC’s lack of popularity here are the poor measurements of a 15 year-old version of the ATC SCM19, one of it’s entry level passive range. It should be added that the measurements are poor relative to its inflated USA price ($4000 a pair vs $2700 equivalent in UK/Europe). That said, there’s no certainty that the latest version (v3) would measure significantly better.
There are objective measurements of other ATC models elsewhere on the internet which correlate with Amir’s findings, but you’ll need to hunt those down yourself.
ATC’s excellent reputation on other sites is probably down to its line of active speakers found in many top recording studios over the years. People who spend lots of money on recording studios should know what they’re doing, right?
This reputation as a ‘pro’ speaker manufacturer inevitably influences the numerous subjective reviewers who rave about these speakers. I don’t know much about psychacoustics, but the idea that what you see and believe you know about a speaker affects your perception of its sound is a convincing one.
I think that there’s a general consensus that the smaller ATC entry level speakers are particularly bass light (relative to ported, similar sized speakers), and would benefit from a subwoofer.
