This isn't accurate. Google's search ad auction started as a generalized second-price (GSP) auction[1][2], which is not the same as VCG. In particular, GSP is not truthful, while VCG is.
The display ads auction (formerly DoubleClick Ad Exchange, now Google Ad Manager) has always been separate, and it used to use an Optional Second Price (OSP) auction[1]. It's transitioning to a first-price auction for the reasons mentioned in the blog post you linked to. As stated in the blog post: "This change will have no impact on auctions for ads on Google Search, AdSense for Search, YouTube, and other Google properties".
The display ads auction (formerly DoubleClick Ad Exchange, now Google Ad Manager) has always been separate, and it used to use an Optional Second Price (OSP) auction[1]. It's transitioning to a first-price auction for the reasons mentioned in the blog post you linked to. As stated in the blog post: "This change will have no impact on auctions for ads on Google Search, AdSense for Search, YouTube, and other Google properties".
[1] https://en.wikipedia.org/wiki/Generalized_second-price_aucti...
[2] https://www.benedelman.org/publications/gsp-060801.pdf
[3] https://arxiv.org/pdf/1204.0535.pdf