Why is the lead synth sound used so much in J-Pop music?

I’ve noticed that in contemporary Asian music, especially Japanese music, which is basically the OG reference for modern Asian music, they use a lot of synth lead sounds in their instruments. This sound is usually the main focus, and sometimes it pops up here and there. It’s become such a signature sound of J-Pop that if you hear it in a Western song, you'll probably think, "This sounds so J-Pop-ish."

For those who might not know what I’m talking about, here’s an example.

I picked the instrumental version to make it clearer. You can hear a clear example of this in the intro of Juju's cover of "La La La Love Song" by Toshinobu Kubota, a classic J-Pop track.
Listen closely from 0:00 to 0:17.

Here’s the video link: https://youtu.be/ysNv9JSM_M8?si=C4nBZ9SuLN7xlHhj

I’ve just picked one example because I’m sure most of you will get exactly what I mean right away.

Lastly, I’d love to hear your thoughts and any examples you have because I’m always down to discover new songs—I’m really into this sound.