Some websites probably do have settings around this, but that gets to a point someone else mentioned: you would have to basically design, build, test and mainta

Some websites probably do have settings around this, but that gets to a point someone else mentioned: you would have to basically design, build, test and maintain two UIs. Except now with the kicker that one of those layouts is only used by the 5% of your userbase that both knows that the option is available and chooses to take you up on it.