Trade Companies and Economic Victory

The Endless series are great 4x games but their victory conditions are quite basic. Currently the economic victory is simply to collect a certain amount of dust.

My idea is to base economic victory around trade companies. At the beginning of a game each faction would have a unique trade company(something like a slavers guild for the Cravers, a gambling conglomerate for the Lumeris etc.). The goal for economic victory would then be to buy out each of the other unique trade companies.

A company would be purchased through the marketplace for an amount of dust proportional to the output of the company. A faction's unique company could only be purchased once all their other companies have been purchased. When a company is purchased it is removed from the game and a percentage of it's output is added to the unique company of the buying faction. The previous owner then receives the dust used to purchase the company. That would cover the offensive side of the economic game.

On the defensive side the first step would be creating more companies as an opponent has to buy them before they can take over your unique company. In addition an investment can be made into a company to increase the cost of buying it. For example if the owner of a company invests 100 dust into it then another player must pay an extra 200 dust to purchase it. In this way a player could choose to spend the dust gained by another faction buying their company to either invest in another to sandbag it against take over or use the extra resources to help accelerate their attempts at another victory condition(ie. hurrying production on new ships for military conquest).