Why no ghosts, Yakkhas, devas and spirits in the modern times?

This might be a more theoretical question than a directly practical one. I routinely see creatures of different realms approaching humans in the texts. and not just to enlightened ones like Buddha and some of his disciples, but even other far-from-liberated regular monks and householders. Now even though I believe, and to certain extent, understand other realms of existence, it nonetheless remains a mystery to me why would these creatures only appear exclusively in those times and not nowadays. Why do you think it could be the case? I doubt the texts are wrong, although that possibility can't be excluded - especially in the sense of exaggeration etc.