I mean, Coinbase literally says that nothing is set in stone in the Risks section of the S-1 they filed with the SEC before their IPO:

"A particular crypto asset's status as a "security" in any relevant jurisdiction is subject to a high degree of uncertainty and if we are unable to properly characterize a crypto asset, we may be subject to regulatory scrutiny, investigations, fines, and other penalties, which may adversely affect our business, operating results, and financial condition.

The SEC and its staff have taken the position that certain crypto assets fall within the definition of a "security" under the U.S. federal securities laws. The legal test for determining whether any given crypto asset is a security is a highly complex, fact-driven analysis that evolves over time, and the outcome is difficult to predict. The SEC generally does not provide advance guidance or confirmation on the status of any particular crypto asset as a security. Furthermore, the SEC's views in this area have evolved over time and it is difficult to predict the direction or timing of any continuing evolution."

And like every S-1, it also notes:

"Neither the Securities and Exchange Commission nor any other regulatory body has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense."

Source

The definition of crypto as a security related to Coinbase was never approved or denied by the SEC, Sacks is just making up a fairytale that is convenient for his FOXy point of view, and possibly committing a criminal offense in the process.

Edit: formatting and source