Probably that. I know my 10 year old nephew had a Neymar top a few years back. And their Jordan link up is quite popular with some demographics. I think they're popular with neutrals because of Mbappe, Neymar, Messi and things like the Fifa games etc.
Just taking Japan as an example, there are three PSG shops in Tokyo, plus others in Osaka. How many have Liverpool got? Plus, PSG have gone to Japan both this summer and last. It's a wealthy market of 120m people, who want the original kit, not knock-offs. And just like bands who tour there sell more albums, the same is true for sports kit.
Liverpool have tended to focus their pre-season shenanigans on SE Asia, where there are lots of Reds fans, but not so much discretional cash for a £60+ jersey. And also lots of garment factories turning out knock-off kits which make the club precisely nish.
The Asian pre-season tours aren't great preparation in the sporting sense. But the club may be missing a trick commercially.