I think about EA market, top EAs sold well make good performance soon.
However, these EAs are all doomed because there's no viewing of the further future.
The problem is, review can control all buying behavior.
Good results soon, Good reviews soon.
But bad result soon (and more profit future), Bad reviews soon (and the reviewer leaved and remain the tatoo forever)
That is the reason mechanism Grid EA sold well and won't sell pure strategie's EA.
The buyer you, be careful to choose the EA on the market.