To justify spending that money, they'd have to think they'd get better returns on their R&D than shareholders could get elsewhere (e.g. by just buying the S&P 500).
It is quite difficult to beat the S&P 500, and they're saying they don't have any ideas which can.
If the shareholders don't think the R&D is going to be profitable then they can sell their own shares. It doesn't seem like the company should be making that decision for them.
More to the point, if the company is seeing such great profits then their competitors should be undercutting them. If they don't have competitors then maybe they should be regulated more like a utility and give that money back to the customers. Stock buybacks usually end up being just a handout to the rich, which they don't need.
> If the shareholders don't think the R&D is going to be profitable then they can sell their own shares
It's not that the companies aren't profitable, it's that past a certain point their money is more valuable as cash to their shareholders than anything the company could use it for.
It is quite difficult to beat the S&P 500, and they're saying they don't have any ideas which can.