"Monks" includes everybody?

I have often heard that in many places in the *sutta*s where the Buddha says *Bhikkave*, (monks!), he really means to include the four *parisā* (assemblies), which includes lay male and lay female devotees. Therefore, it is said, that teaching applies to all. Where did this idea get legitimacy? Is there any mention in the canon itself? I can readily see why one would **wish** it were so (why would one ignore all the wisdom because it's not spoken directly to oneself) but that doesn't mean it **is** so. I'm also interested if this explanation is offered in Mahāyāna where the meaning of saṅgha itself is broader, as I understand. Also within Insight/Theravāda circles, is there a difference between the West and traditionally Buddhist countries like Myanmar, Sri Lanka, Thailand in the reading of this word. Any historical insight into whether the West was influenced by the early arrival of Mahāyāna to its shores, for example. **Edit:** I am aware that it makes sense to view the teachings as applying to everybody. Please note that the question is more specific - **is there canonical support (in any canon) for this interpretation? Or some other historical information other than using our own logic.**