I have a strong suspicion we are going to see eSports team insignias released as "official team merchandise" products, with proceeds from spray sales going directly to fund those teams. The reason for making that sort of product consumable is for fans to provide ongoing support - literally - not with a single product that then lasts forever.
That's actually a neat idea, but even assuming it's the case, it doesn't demand that the limited lifetime factor apply across the board. I'd imagine players would accept some sprays being temporary items in the case of them acting as a method to directly support their favourite player/team.
I don't believe their next game will consist solely of MTX consumables [if sprays remain unchanged].
Well, neither do I, to be clear -- they'd be the rule to which there'd be some notable exceptions (I realise you disagree with this as well, but I figured I'd clarify).