I hear the appeal for the charm of guides, but considering tourist guides as a fundamental pillar of destination choice is a view that doesn't always hold.
Their role is more often a support element, refining decisions already sketched out by other practical factors.
In reality, the availability of flights and accommodations, as well as budget, are the primary filters for most travelers.
A guide becomes valuable once the destination is chosen, to refine the itinerary or find local gems, like a caterer for an event after fixing the date and place.
It's a bit like saying that flower choice is the first step in organizing a wedding, while the date and place are obviously the foundations.