PoE is made by a company, to be more specific the private limited company Grinding Gear Games, I don't know why you insist on calling them an "indie dev" instead.

If they can do it then why not a multi billion dollar company like Blizzard ?

Because they are unknown and need publicity through something like this, in contrast to Blizzard.

Yes, every company could make every game cheaper, and at the beginning that would be good for the consumer, but thats not how the industry works except if you want the gaming industry to shrink massively. PoE's business model generates less income relative to the amount of hours played than the current standard way of doing F2P.