If they spent 15% of that ($2.1 bil) on support, with say a mix of 2/3 low pay ($100k/yr cost) and 1/3 high pay ($150k/yr cost) people... they could hire 18,000 additional support staff and still show a great profit.
That works out to 30 mil support hours assuming 1680 hrs/yr (35 hrs * 48 weeks) actually spent on support. They could probably hire twice that many people by hiring some people in less expensive areas.
To sum up, Google puts making a more money ahead of better support. It's their right to do so, but it not "unrealistic" for them to provide much better support.