Microsoft has the luxury of failure also, but when they tried to compete with Google they failed. Microsoft are in the same markets that Google makes a huge amount of money from and yet they failed on most fronts.

I think the safest way for Google to make money would be to not innovate or create any off the wall projects, and then just return the money the money to shareholders through dividends or share buybacks.

Just looking at the current stock price of Google $909 and Earnings per share of $33, this means that IF Google returned the entire earnings to shareholders it would take 27 years for the shareholders to get their money back and THEN after this 27 years they would start to get a return on their investment. This assumes no growth, and Google has grown significantly but there is no guarantee they will grow in the future. Even if they do grow significantly it will still take a very long time to get your investment back.

There are unknowns that could completely disrupt Google's business models for example what if all search became voice based (siri-like) with better AI. Or what if a competitor develops much better AI capabilities into their search.