The irony is most people watching Pokémon now weren't even born when Misty was part of the show. If you count from 2003 till now, over 80% of the current fan base grew up with the show with any of the later generations and of course Ash's later companions. It's likely why each new female companion becomes popular one after the other, the days of people believing the show couldn't go on without Misty, Brock or the original trio in general is long over. 20 years over.

Even all the kids who grew up with the DP era in 2006/2007 are now adults hence their nostalgia for it. It feels weird knowing only 30 year olds have grown up with the original series but with the passage of time it was inevitable.