You can still buy stuff from the website of the PS Store. Will this be removed too? https://store.playstation.com/en-us...rch_{ps}&utm_source=Google&utm_term=ps-se-717 That is the NA Region Store. EU store also has it too here: https://store.playstation.com/en-gb/grid/EP0017-NPEA00266_00-DCUOLPS3LIVE0001/1?relationship=Add-Ons
I think the point is seeing as the support is being pulled on Jan 31st, then the product should no longer be available for purchase as of NOW!
If you purchase an item now...... you will be able to use it once you upgrade to PS4. If they completely remove the option to purchase right away..... I can already see the complaints when some people finally upgrade to PS4 and complain that they missed out on some items because they could not purchase them on PS3.
To be fair, a lot of PS3 games are closing in 2018. PS3 is 11 years old. Killzone 2 and 3 are closing too after being online for like 6 years. Things like this happen but it not the end of the world.