If I were starting a website today, I would not consider Google traffic anything more than a bonus.
They are arbitrarily penalizing websites and asking webmasters to perform ‘good faith’ efforts to get rid of links they didn’t acquire in the first place. Other webmasters can destroy your sites ability to rank in Google and there is little you can do about it. There’s no way you can ever feel comfortable considering how much you don’t control over the future of your Google traffic.
Try doing a stress test for your site to determine what would happen if your organic traffic in Google declined between 50% to 90% overnight. Can you survive? If not, then it’s probably time to start coming up with some contingency plans.
What is your margin of safety?
Warren Buffett describes Margin of Safety in terms of tolerances:
When you build a bridge, you insist it can carry 30,000 pounds, but you only drive 10,000-pound trucks across it.
The same concept should apply to your website.
How much traffic or how many orders do you need to keep the lights on or feel financially secure?
Whatever that number is, make sure you can attain those targets without accounting for Google traffic. This is certainly not easy, but it will make your website and business stronger over the long run.