Breaking format changes is not such a major issue, they happened before: kdb → pre-2.08 kdbx → kdbx3 → kdbx4. If the new format is worth it, popular apps will adopt it within a few years — while still supporting older formats. Users would just stick with their current format until the ecosystem catches up, as it happened with KDBX and KDBX4.
wps|4 days ago
KeePassium|4 days ago
That said, most of the concerns raised by the article — outdated schema, inefficiencies, governance issues — call for a new iteration of database format, but not necessarily SQLite. However, we would still be debating how to represent entry templates and how to accommodate features that stretch format's initial assumptions (be it multi-URLs or smart groups). We may still discover that passkeys need more fields than initially foreseen. Then someone would come up with item-level access rights scheme. Then something else.
All of these are already possible with XML+Gzip, just as much as with SQLite/SQLCipher. The main advantage of the latter is the standard, multi-platform library with a permissive license, instead of KDBX' specialized parsing. Switching to SQLite would probably lower the entry barrier for new apps. Which would be a good thing on the surface (more choice), but could end up with the same devil-in-details bedlam as the status quo.