My own theory is, it has to do with the rise of do-support in English. This is from etymonline:
The nearly universal use of to with infinitives (to sleep, to dream, etc.) arose in M.E. out of the O.E. dative use of to, and helped drive out the O.E. inflectional endings (though in this use to itself is a mere sign, without meaning). Commonly used as a prefix in M.E. (to-hear "listen to," etc.), but few of these survive (to-do, together, and time references like today, tonight, tomorrow -- Chaucer also has to-yeere). To and fro "side to side" is attested from mid-14c. Phrase what's it to you "how does that concern you?" goes back a long way:
Huæd is ðec ðæs?
[John xxi.22, in Lindisfarne Gospel, c.950]