I believe, therefore, that it behoves the better educated among us at the very least not to exacerbate the problem by allowing such misconstructions as *between you and I to pass unchallenged (or indeed those "authorities" who construct utterly spurious arguments in an attempt to inveigle us into accepting them!)
People have been bemoaning the decline in standards in English since people such as Cheke and Mulcaster fulminated about the introduction of inkhorn tems into the language centuries ago. Conservative speakers of each generation have tried to conserve the language of the previous generation, though, for some strange reason, not the the language of the previous century.
In my lifetime, I have seen several constructions pass from completely unacceptable in British English to widely used and accepted. These include: the split infinitive, the
shall/will distinction, 'accusative'
who, prepositions at the end of sentences and "It is me". "Between you and I'" will probably join this list, whether we like it or not.
Discussion about whether such forms
should be considered acceptable or not is often fruitless, because some of them
will become acceptable whatever anyone says; some will not. We rarely know until after the acceptability has become established.
The mere labelling of arguments as 'utterly spurious' does not prove them to be so.