That seems to me that that would actually create more smurfs, as the struggle of leveling/acquiring runes is a fairly big disincentive for people to create one.
Maybe your thing might make the 1-30 world slightly less smurf-y (albeit not entirely, since one of the many reasons for smurfs is for people to be able to play with their low leveled friends without having the associated mmr making it really rough on their new friend), but there'd be a whole world of smurfs in bronze/silver/gold.
Precisely how 'alts' would work might vary, but however you do it, it'd spoil someones intentions behind smurfing, so you'd still get them done the traditional way.