It certainly can be true, but I think it depends on a really large variety of things.
For instance, my parents never had a guest room until after both my brother and I had moved away from home. It wasn't until then that they had a spare bedroom with a double bed that they could consistently offer to guests. Before that, they had a foldout couch in the den (a public room without doors where our computers were) or one of us kids got kicked out of our bedroom when someone stayed over.
However, I know that I personally will always try very hard to make sure I have some sort of guest room available, even if it's combined with an office or some other function. My in-laws live extremely far away, and always will, so they won't really be able to visit unless they can stay with us. For our own convenience and their privacy, it would be nice to have an actual spare bedroom that wasn't used for anything but guests. It's not hugely common to have an attached bath (that isn't shared) outside of a master bedroom, although if I were building my own house and could swing it, I'd probably want one attached to the guest room.
In the end, I think it comes down to priorities. People who know they will have a lot of visitors who need somewhere free to stay are likely to prioritize a guest room of some sort if they value those visits. People who don't have a lot of visitors, or who don't particularly like having guests stay with them, are less likely to prioritize a guest room of some sort. And, of course, circumstances play a role, too. If I end up living in a part of the country where housing is very expensive, I might not be able to do better than a pull-out sofa in the living room. If I end up living somewhere that has less expensive housing, I might be able to afford a house large enough to have a dedicated guest room.