...all the time and effort you spent on it will be wasted
You seem to be a novice in SEO; otherwise you would have known there are multiple avenues which enables SEO. And it never crashes with dilution of one of the factors. Albeit it impacts SERP presence temporarily and that's why SEO sustained and is here to stay.
Google is spending time and effort to make G+ a more followed tool. This author rank in a way complements that. And if you ignore now because of thinking that it can be debarred later then its laughable because any updates that google favours when embraced quickly help in propelling SEO.
Since the emergence of SEO, there were some factors which were accepted and got evolved with their importance while others perished. We have over a decade experience in online marketing. And we know when one medium stops then other avenues would surely come out.
And still if you cannot agree and lets agree to disagree. No point in discussing with someone who don't want to adapt as per new conditions :)