It's not quite that extreme in terms of life, you will not die. However the same can not be said for your website, unless it is mobile friendly you may see your position on search result rankings drop off dramatically. This could have significant consequences for your business. Namely that you no longer appear as prominently in the search rankings. Google is dedicated to serving their search customers with great search results. This means that the websites that they provide to their users should themselves have a good user experience. With the increasing use and subsequent importance of mobile browsing Google has placed a requirement for websites to have a mobile friendly option. If they do not then they will not perform as well in the Google search. We have noticed this with client websites who had not updated their websites to a mobile friendly version. Following the actual, noticeable decrease in their online performance they took the decision to switch to or make a mobile friendly version available.
This is not just Google enforcing a new change and punishing websites. It actually makes sense. If more people are using mobile, then it is good for the users to be able to see your website on their mobile device. What's good for them, is good for you. If a user comes to your site, but finds it difficult to navigate it, do you think they will stick around? Or do you think they will find a website that has been optimised for a better mobile experience. One where they can easily find what they are looking for?
Don't let your business suffer from this change. Improve your customers browsing experience with a mobile optimised site, and get rewarded by Google in the process (avoid punishment from Google).