Does anyone know if this will have any impact on Gmail backup tools such as:

https://github.com/jay0lee/got-your-back

Or the long term sustainability of such projects?

I've found gmail's own data export tools to not work at all for any inbox of a considerable size (100gb+) - so third party tools are the only way to actually back up / migrate email data.

Without such tooling, relying on Gmail would be a huge mistake for anything remotely important.