Popular names become popular for a reason - and as the reasons don’t go away overnight, neither does the name. Oliver and Olivia are classic names and, while they might have had a longer than usual ‘moment’ over the last few years, they’ve never really gone away, unlike names such as Florence and Esme, which are considered cute now, but would have been seen as horrible old lady names in the 80s and 90s. Although I’ve seen a couple of people on this thread saying Oliver and Olivia will date over time, I really don’t see it. An Oliver could be 5, 30 or 50, as could a Jack, Chloe, Harry, Sophie etc.
Names that are considered very modern at the time often date more quickly. I can’t imagine anyone calling a baby Sharon, Tracy, Wayne or Gary now - they went from popular to punchline in a few years. ‘Yoonique’ names, rightly or wrongly, can come across as a bit pretentious/tacky, and are usually more about the parent wanting to stand out than anything else. Even more mainstream names start to sound ‘of their time’ after a few years - so while Matthew, Stephen, Julie and Louise don’t sound odd or horribly dated, I’d assume a Julie was over 30 rather than under 10. I can see the same happening for the once old-fashioned names revived in recent years - Alfie, Archie, Grace, Millie etc.
Oliver and Olivia, or other regular chart-toppers, might not be ‘original’ or exciting choices, but I think for a lot of parents, that’s exactly the point.