What I mean by this is e.g. you can already use Linux on a desktop and it's generally okay (or even good sometimes), however things like LibreOffice are absolutely unusable in terms of performance, functionality and user friendliness compared to e.g. Keynote or even Pages on macOS.
Multiple governments having to solve essentially the same issue on a global scale is a unique opportunity to save costs by working on open source together, and get funding and direction that's never been available to OSS before.
The problem is that the tech independence is being pushed by government who want more control - not less. (Not speaking specifically of France and this instance, but looking at the anti-encryption rules that the UK and Ireland are pushing)
From that standpoint, I imagine the "solution" here won't be to push an open source alternative, but a closed one that they to control.