Fortunately it doesn't take much of an imagination to figure out how supply and demand works.
They have an infinite supply, and a dwindling demand.
A suggestion is charging for new versions, but that's broken as well, for a myriad of reasons including piracy.
It's taken years for many companies to figure that out.
There's a reason why Unity gives their stuff out for free.
There's a reason why Adobe does Photoshop subscriptions.
There's a reason why so many game engines fail.
Scirra can't do what Unity does because it doesn't have the huge/successful user base.