What evidence do you have that it's only a small boost? That may be the case for very specific searches. But if you search anything where there is a lot of competition between publishers (coverage of major news stories, product reviews, etc), Google serves almost exclusively AMP results, with the exception of the odd result from Wikipedia or Twitter. Failing to implement AMP would be suicide for many publishers.
The author should clarify that they're taking extreme measures, but that this isn't required to not use AMP.