Google and the like aren't borrowing money to light on fire with their misguided attempts at new products, they're supplying it themselves from their highly profitable core business lines. Therefore their failure to produce returns aren't an indictment of current interest rates.

What they probably should start doing is paying a meaningful dividend to shareholders because they've repeatedly demonstrated they aren't capable of producing additional shareholder value with new product/business lines, but I don't see that as very likely in the near to medium term.

That's because it's more risky for the careers of the decision makers to hand cash back to shareholders and say they don't know what to do with it than it is to lay claim to some moonshot with a < 1% chance of success.