We have inhabited both the actual and the imaginary realms for a long time. But we don't live in either place the way our parents or ancestors did. Enchantment alters with age, and with the age. We know a dozen Arthurs now, all of them true. The Shire changed irrevocably even in Bilbo's lifetime. Don Quixote went riding out to Argentina and met Jorge Luis Borges there. Plus c'est la même chose, plus ça change.