Just kidding. Nobody knows the future value, least of all CxOs whose compensation is tied to quickly increasing the stock price now, regardless of the distant terminal value.

Yeah, well, I guess I was being a bit generous suggesting that buybacks were a wash on average : )
They're almost certainly done above fair value on average across time and different companies, and therefore value destroying in aggregate for continuing shareholders.
The main witness for the prosecution is how pro-cyclical the buybacks are: low buybacks when the market is low, lots when the market is buoyant and prices are over the top.

Even when buybacks are done at seemingly high valuations, and even when they ARE slightly value destroying, sometimes there isn't another really good choice.
I can't really think of anything else that (say) Apple could do with all that money. The goggles were expensive to develop, but not THAT expensive.
Buy Berkshire shares?
Even that wouldn't soak up all that spare cash flow for long.

Jim