supply-side craponomics never said that companies would simply hand over profit to employees in the form of higher wages. that's not consistent with any model of economics.
voodoo economics instead expected that huge mal-wart profits (or otherwise shifting more resources to sellers) would create richer investors, who would then create new businesses, which would then higher more workers and make more resources more readily accessible and so on. alternatively, mal-wart would themselves expand, leading in principle to a similar result.
mal-wart workers would then benefit by switching to newly available better jobs, or, only then, mal-wart would be forced by the market to pay more to keep workers.
of course, the big flaw is the economy is a delicate system that thrives best when kept in a careful balance, so stimulating the supply-side really only works when supply is weak. that hasn't been a problem for a long time and yet the supply-side stupidity continues because few things sell as well as greed, just so long as you don't call it by its proper name.