It's fun to speculate, so I'll throw in my two cents.
No, I don't think we're ever (or at least for the next 5-7 years) going to see an Intel Mac again. It doesn't really make sense. Apple has spent tens of billions on the R&D for their own silicon, so as to be able to control their entire stack. Why would they want to undermine the message that "Apple Silicon > anything else" by launching a new Intel Mac.
Now, I'm not a "Pro" user, so perhaps there's an industry reason to keep intel around for a bit. Maybe there's some highly specialized software that simply does not run well on Apple Silicon right now - things like Houdini, Maya, along those lines. That would probably be the only reason to launch a refreshed and updated Intel Mac.