Valid point you’re making, but I’d say having to lock your doors goes back quite some time in general. As in, there being a need for it at least sometimes. There being an option for it, really.
I grew up in a house where we didn’t lock our doors. Well, our mom liked to, but she was born in the capital area and not in the quaint little village where I was born.
Still, I wouldn’t consider it a “modern problem” unless we’re talking about the Modern Era, which spanned the years 1500 to 1945. That I would say was probably quite a good time to be a burglar, with there being something worth stealing, but locks still being shit.