Seems Millennials are smarter than we give them credit for.
I believe the powers that be thought of this before the millenials. One giant stumbling block to a 3rd party is the gerrymandering of the congressional districts.
In recent years, many of the states have "addressed" the gerrymandering issue by amending their constitutions to set up bi-partisan re-districting commissions. These commissions were sold as being the end of gerrymandering. This was a complete lie. The "bi-partisan commissions" simply enshrined the 2 party system into the law. This insures that the dems and repubs are free to get together after every census and carve out safe districts that will never allow for a 3rd party challenge.