We also know because one of the primary writers of the bill said so in several speeches.
I've seen this repeated at least a dozen times so far, but not a single citation...
Most people can't or won't weasel their way out of a smog check,
I don't think smog checks are as ubiquitous or effective as you think they are. Yes, California has a very strict and effective system, but in my state, failing a smog check only means I have to spend $150 for a diagnostic and I get a waiver until then next check. People living in incorporated county areas aren't even required to submit to emissions testing.