It seems an age ago, but it is not, when executive dining rooms, toilets, forms of address were the norm and rigorously reinforced. Some of these behaviours can still be found in golf clubs and some organisations but not many. The modern way of thinking is to do away with most of this if not all these behaviours and rules that reinforce them and replace with a more informal way of working.
This informality should not be confused with casual behaviour. Targets and goals still need to be achieved, no matter what people are called and what they wear to work and appearances must not reflect a casual way of working, The tech giants all espouse the informal way of working, chill out rooms, table football etc. etc. but they are relentless in their corporate drive otherwise they would not be successful.