the old (non) adage - absence of evidence is not evidence of absence.... just cos we haven't found a medieval shopping trolley doesn't mean they didn't have them... or would have had them if they'd thought about it!

Having been involved in hand making things as archaeolgical experiments, let me tell you, until mass production came along, you only made things if you are really going to get a benefit from it. It's so time consuming it's unbelievable.