Ok, most of us have doormats and a lot of them say “Welcome”. And in general, we have always left ours out 24/7. maybe a seasonal one is changed out.
But after listening to two olde songs that mention some variation on “The Welcome Mat is out!”, I wanted to know; was there a time where you put the Welcome mat out only when you wanted to receive visitors?
Some of us have a door mat that says “Go Away”, and leave it out all the time. That’s the new one that took me a long time to find. The old one said “Welcome” on the other side and for some reason my wife would turn it over to that side when actually welcome guests were expected.
Doormats, of course, have been around forever and my WAG is that adding the word, “Welcome” got started by an enterprising maker linking his product to the Bible. “Therefore welcome one another as Christ has welcomed you, for the glory of God.” Romans 15:7
I think the phrase is and always has been metaphorical. To tell someone the welcome mat is out is just another way to say they are always welcome.
How can you have a welcome mat that doesn’t say “Welcome” on it? It could be just any kind of mat then. Unless it’s getting to the point that the OP is asking about, do you physically put out some kind of mat just for welcome guests?
Of course I don’t think the phrase “Put out the welcome mat” is tied directly to a physical mat anyway, it means you take actions to welcome someone into your home, tidying up, offering your guest the good chair, bringing out refreshments, gushing about how happy you are to have them, the things you don’t do for just anyone who might cross your threshold.
I have some friends with a cabin out in the woods. Their welcome mat is “turned around” with the idea that you’re being welcomed into the great outdoors whenever you walk out the door.