Audio gear is always constantly evolving and getting better so it is only natural to move with the times. Also taking into consideration that the person gains more knowledge along the way is very important.
There was a time when Z always recommended the Fiio E10K. Back when that was still really a thing.
Now days it is a piece of trash in comparison to the other products in it’s price range.
Then the Objective amp and DAC came out and that was the absolute shit. It is still good. But there have been better things since that have been put out there, some of which specifically to replace them.
As new things come out and you listen to better things, you are going to naturally replace things along the way with those newer better things that now exist.
And yes you also also have to consider yourself in the equation. Every person’s ears are different and that changes what everyone enjoys. Age also coming into play.
Then there are people who have barely heard any hardware and also people who are just completely ignorant (people that buy Beats by Dre because they think it is the best sound ever for example).
Same reason why some people swear by the audio technica m50’s. Go those things were terrible.
But hey some people loved them.
Music is just one of those oddly very subjective and more so than other things that you would think are more subjective. Like fashion or favorite food.