In the past there were redirects to more sites. However those sites have highly specific scope. For example, on many sites it's cool to ask how to use an X, and to mention you have the Y brand or model, but it's not cool to ask what X you should buy or if Y is a good X.
Generally speaking people on SO don't know those nuances. They just know "this doesn't belong here." So they sent bad migrations over. When questions were closed and deleted on the target site everyone felt bad. So that doesn't happen any more.
I once suggestedonce suggested that you be able to send to sites where you had a decently large rep, but that never happened.