Has this really happened to you? I got the WiFi QR printed and hanged in my living room, and to this day nobody has ever had a problem. QR might seem too techie, but they are so pervasive that everyone knows how to use them.
Nope. I know people first-hand who don't. Hell, even I don't know how the average person does it. My own phone's camera app doesn't detect them so I had to find a random 3rd party app and trust that it's not stealing the info. In fact I'm not sure I've ever used the stock camera app on any phone to scan a QR code before. For some folks it might be "press Camera and scan", but for others it's way harder than it looks.
My guests doesn't ask for the WiFi pass, they see the QR hanging and ask "what is this QR for?", "It connects to my WiFi", and they immediately try it (succesfully) out of curiosity, "It's cool, how is it done?". The don't understand the magic behind, but don't need a guide to use it.