Except for one big exception. If the third party is replacing one of the major parties, then under the right circumstances it does work.
Case in point: Slavery was splitting the Whigs into about five splinters. Abraham Lincoln came along and led the splinters which were anti-slavery as well as states rights into the Republican Party. Those whig splinters which still wanted slavery or more government disappeared.
Right now we have splinters of the Republican Party who are RINOs, liberal Pubbies, moderate Pubbies, etc., etc. Look at the gatherings over the last month. Underlying almost all of them was a feeling of let's get back to conservatism. That could be the catalyst, with somebody to lead, which could form the new party.
Touche’
Yes, I see your point and agree totally. I stand corrected