a buyback would make ZERO difference if Apple goes out of business (do you really beleive what you just said!)
The reason is each shareholder would have a larger stake in the company with a buyback. But seriously, you really think Apple will go out of business in the near future?
Bottom line is if a company goes out of business the stockholders usually get close to zero. First lawyers get paid, debt holders, employees, vendors, ect. Then finally shareholders. Your fear is really the last thing I'd ever take into account. You will have years of warnings to sell your stock before Apple goes bankrupt