Starbucks' (NASDAQ: SBUX) recent announcement that it would eliminate plastic straws from its restaurants by 2020 elicited a collective shrug from Wall Street as the stock ticked up 2% on average volume on an up day for the market, but the decision could be an important catalyst for the coffee king at a time when it desperately needs one.Starbucks shares recently sank to a three-year low after the company said in June it would close 150 underperforming U.S.