I would imagine that efforts have been made to bypass the roasting process. Environmental laws made it necessary to add a sulfuric acid plant to the roasting operation to capture and recycle the sulfur dioxide emissions. If they couldn't sell the sulfuric acid at a competitive rate, the operation ran at a loss. A direct reduction of sulfide would be the solution.
By the way, that foaming and fizzing you see is hydrogen being released as the zinc is converted to zincate by the molten sodium hydroxide. When the gas evolution stops even though sodium hydroxide is still available, it means you have pretty much removed all the zinc. Antimony and bismuth should similarly form antimonates and busmuthates, albeit more slowly, tin should eventually form stannate, and lead should react the slowest of all.