As I said, impractical, not a solution.
> If world does not match your view it may be you who is outlier.
Looking at the amount of software that does follow the base directory specification, actually you're the outlier insisting on obsolete conventions.
You and a bunch of other developers insist on those things, in reality that is the actually harmful behaviour for open-source.
Interestingly but yet non-surprisingly, that insistence very often goes in hand with the stubborness to stay on obsolete mailing lists, ugly user interfaces, insecurity by-default, git-email, buggy issue trackers, 80-column commit messages, obsolete security standards and practices and so much more.
> I quite like current convention - hidden files in $HOME belong to applications.
The future is now, home folders aren't to be filled with trash. Move on or stay behind, seriously.