Outdated advice about automated usage of PageSpeed via PSI / lack of API v5 CLI tools & recording/comparing system

[MarcusJT]

Page Affected: https://developers.google.com/web/updates/2014/06/Automating-Web-Performance-Measurement

What needs to be done?
This page is all about automating the use of PageSpeed but the linked CLI tool PSI is only for API V2 (which is no longer available) and appears to have been abandoned, so the page is pretty useless.

What CLI tool can be used right now with API V5 and will be fully supported by Google to ensure future compatibility with V6, etc?

And more fundamentally, why is there no readily available solution to the universal problem of needing to perform PageSpeed checks across a range of pages (100s or even 1000s) on a regular basis, recording metrics (i.e. not just the overall score but TTI, etc) and being able to compare them over time? Surely this is something that Google should build and gift to the world so that we can all focus on improving the actual performance of our pages instead of everyone first having to come up with their own way of monitoring PageSpeed in the first place?