About Blitzcrank's Poro Roundup!

[Thanks Riot for noticing my mistake on putting this in the wrong section and letting me know!]

So..I saw that its 'cabinet will close' on the 21st. But...why? Its an entire game that's only available one month of all time, why can't it be available to play whenever? And which the answer might be "They offered to download it on your phone n shit" but I don't have a phone that supports it...which really fucking bums me out, so why can't it either be permanent in the site, or available to download on PC?