Adam Smith "sold" capitalism on the virtue of "free and fair markets". Capitalism, as a practical understanding today, is the supremacy of capital, oligarchist protectionism, and corporatism. Only fair markets (those without coercion and lies, including structural coercion) are free. Adam Smith did not define/sell capitalism as structural coercion of society to maximize ROI for those with capital. Actually the opposite, where "perfect competition" was supposed to result from free and fair markets. Monopoly/cartels generate higher ROI than competition.

UBI/freedom dividends is the path for free and fair markets for labour. It also naturally increases ROI, where investment includes work/time, where the freedom to refuse unfair work means higher pay for work, including higher returns on capital/management, if competition needs higher returns for their work too. But, most important to ROI, redistribution and high pay, means significant increase in demand/GDP, and more work available to satisfy that demand.

The reason UBI is resisted, is not that the rich cannot get much richer from UBI. It is that UBI redistributes power instead of wealth. Those in power, have more power under slavery than by giving away their power (freedom) to the people. Oligarchy needs control over power to protect their oligarchy. After your first $B, what is the point of more money if not to enforce harsher slavery to limit competition to your next $Bs.