This assumes what needs to be proven. Namely, the degree to which the wealth of billionaries under the status quo regulatory, financial, and tax regime reflects their outsized contributions to welfare.
If we make a number of assumptions (e.g. perfect information, perfect competition, equal initial endowments, etc.) it's tautologically true that great wealth would reflect outsized contribution to preference satisfaction. But these assumptions are wildly unrealistic, and conflict with both everyday experience and historical reflection.
More to the point, we all want our economic system to do more than merely satisfy preferences. Opioid manufacturers cultivated and satisfied preferences to the tune of billions of dollars. The impacts on well-being of users and their communities were, to put it lightly, mixed.