Because first past the post electoral systems always result in a 2 party system due to defensive voting.

Nope. FPTP is the norm worldwide and two party systems very much the exception. Even in the US, it's only been the last third or so of the country's history that two have managed to become so all-conquering in spite of being so unrepresentative.

George Washington, when during his farewell address he strongly cautioned against "alternate domination" of a 2 party system.

Pretty sure he was very much against the concept of political parties in general, rather than having any preference as to how many.

But yeah, the two major parties HAVE pretty much embodied all his worries and more..

Because Americans are woefully uneducated, dis-interested, and preoccupied.

That's a big part of the problem, sure, but the issues of regulatory capture and the two parties themselves being in charge of how the entire system works (including the barriers to entry for everyone else) is MUCH more critical.