I don’t see the 2 party system going away. HHistorically we have been a 2-party system since 1790.

More likely, if anti-Trump Republicans push to establish a new party, either side will prevail and we will be back to two parties, similar to when the Whigs went away and the Republican Party took its place in late 1850s.

More cynically, Republicans will NOT split. They will continue as they are in order to win elections