Complex sentence: McMillan surmises that reducing rent would "create 3 to 6 million jobs" freeing up capital to give businesses a chance to hire people; this would, in turn, increase tax revenue.
Split into simpler sentences: McMillan surmises that reducing rent would "create 3 to 6 million jobs," freeing up capital to give businesses a chance to hire people. This would, in turn, increase tax revenue.