Bill Gates, as noted in your linked article, is against aggressively raising the minimum wage.
As with Warren Buffett, he is in favor of raising the income tax credit rather than the minimum wage. It's a radically better solution for improving wages in the near-term. A too-high minimum wage artificially cuts off the supply of who a business can hire, based on what someone's labor is worth to said business (they have to be able to afford the cost of the labor). An increased income tax credit, paid for via higher taxes on the top ~1/3 income bracket, avoids the problem of pricing low skilled labor out of the market and enables businesses to hire a lot more people whose labor isn't yet worth eg $10 or $15 / hour.
Taxing productivity is an extraordinarily bad idea. It's up there with taxing every search result or trying to slow down computing productivity by abusively taxing cloud computing or smartphone & PC usage.