Yes, I think, in theory, paid for lounge access for economy class is a great thing, but in the case of Emirates simply isn't viable. Offering free lounge access on a certain route e.g. people going to or originating from Bangkok could give an airline significantly better usage and market share, as if one airline was £50 more but my whole family got free lounge access then I would fly with them, over QR/WY/EY.
If KLM or a European airline did that, imagine how much more passengers they could carry. Imagine if BA offered this deal for economy class passengers originating/going to New York, there would be a lot more demand as people would use BA from all over Europe, above maybe Lufthansa or Air France (if prices are similar) because of lounge access.
In conclusion, superb idea but the correct infrastructure is needed to put it into action or a designated economy lounge where passengers can pay for access or get complimentary access if they are on a qualifying route.
If KLM or a European airline did that, imagine how much more passengers they could carry. Imagine if BA offered this deal for economy class passengers originating/going to New York, there would be a lot more demand as people would use BA from all over Europe, above maybe Lufthansa or Air France (if prices are similar) because of lounge access.
In conclusion, superb idea but the correct infrastructure is needed to put it into action or a designated economy lounge where passengers can pay for access or get complimentary access if they are on a qualifying route.