Arnold Zwicky in Language Log discusses the much-condemned phrase “between you and I” in terms of the claim, made by more than one supposed expert, that it “seems to have emerged only in the last twenty or so years.” This is absurd; Shakespeare has Antonio write to Bassanio (in The Merchant of Venice, Act III Scene II) “all debts are cleared between you and I.” William Congreve used it in 1694, Byron in 1805, Mark Twain in 1856; in short, it goes back a long way. Zwicky says:
The facts look complex, but it’s safe to say that the rise of “between you and I” in Late Modern English goes back at least 150 or 160 years, not 20; earlier uses go back about 400 years. There’s no way it can be blamed on modern education, as John Simon suggested in 1980 (see MWDEU), unless Simon was just playing with different senses of “modern”.
In any case, we have here another instance of the Recency Illusion, the belief that things YOU have noticed only recently are in fact recent. This is a selective attention effect. Your impressions are simply not to be trusted; you have to check the facts. Again and again—retro not, double is, speaker-oriented hopefully, split infinitives, etc.—the phenomena turn out to have been around, with some frequency, for very much longer than you think. It’s not just Kids These Days.
He has more examples, and discusses the Frequency Illusion as well (“once you’ve noticed a phenomenon, you think it happens a whole lot, even ‘all the time'”).
By the way, looking up between in the OED I discovered it was two words in Old English, and the object regularly came in between: Beowulf has be sæm tweonum ‘between the seas’ (literally ‘by seas twain’), the 10th-century Blickling Homilies has be us tweonum ‘between us,’ and so on; “thence through constructions like fridh freondum bi twéon ‘peace friends between,’ bi twéonum, bi twéon coalesced into prepositions. (Cf. the history of to (us)-ward, to-ward, toward.)”