I don't think moving to PS5 is necessarily driving closing down the old version of the store. After all, there is still a web store, and it sells (presumably!) PS5 and PS4 games, it's just too flashy to be usable. And the old version served the PS4 plenty for years, and used to serve PS5 as well, it wasn't exclusive to the PS3 and Vita. So if there's no functional requirement to change the store, and the store itself is console-agnostic, I can only imagine it's some marketing initiative to change the UX for branding purposes.
The new webstore is just so *
atrocious*, I honestly can't fathom who approved it going live in the state that it's in, let alone disabling the old store before the new one had at least some feature parity.
Here's a brief list of things you can't do on the new store that were available on the old store:
-Watch preview videos or view screenshots for a game
-View all the DLC available for a game from the game's main listing
-Sort search results or just even content by any criteria... say alphabetically or by release date or price
-Manage a list of favorites
-Manage your download queue across devices
-Initiate downloads across all your platforms (new store is limited to PS4/PS5)
I guess the new web store does the one crucial thing it must... in that it allows you to buy games... for PS4 and PS5 only.
I mean... *Nintendo's* web store is far superior the the new PSN one, and if you are behind Nintendo in online features I think you need to maybe put a bit more effort in.
I mean, look at the store page for the "Golden Week" sale that just started. There's no branding about the sale, no indication of how long the sale lasts (though at least when you view an individual item it lists how long it's on sale), no way to sort the items in the list, no indication of how many items are on sale, no way to filter by platform. It's like the minimal amount of effort you could get by with.