Sony plans to launch a new PlayStation Store on the web and mobile later this month, which will remove the ability for you to purchase content for legacy consoles such as the PlayStation 3, PS Vita, and PSP. PlayStation 4 apps, themes, and avatars will also no longer be available through the web and mobile storefronts once the changes roll out, while content from your existing wishlist will be removed.
https://www.pushsquare.com/news/2020/10/sony_launching_new_ps_store_on_web_and_mobile_this_monthWhile you'll no longer be able to purchase PS3 and PS Vita content from the PS Store on web and mobile, the platform holder is not shutting the storefronts down; you'll still be able to buy content for both consoles using their native PS Store apps, although Sony has been failing to display new releases in the PS Vita storefront for years now.
I'm guessing this is the first step towards closing PSN on PS3 / Vita. I hope Sony has a viable BC solution worked out by then.