Dozens of former Republican officials in talks to form anti-Trump third party
reuters.com
reuters.com
No, it usually means they were Republicans at least in part because they had values that the Republican Party at the time best expressed, and not purely out of tribalism and cultish subservient devotion, and the party changed on ways which no longer matched their values.
The idea that people like ex-Republican strategist and McCain Presidential campaign manager Steve Schmidt, former Reps. Joe Walsh and Joe Scarborough, George Will, and numerous other were “weren’t Republicans in the first place” is ludicrous revisionism (and the same would be true if you said it of many of the Democrats who switched parties especially between the 1960s and mid-1990s.)
When parties changes, people with strong values that corresponded to the pre-change state but not the post-change state are likely to leave.
For example, if I strongly believed abortion is murder, I would hold my nose and vote Republican every time, but that doesn't mean the fiscal responsibility wing of the party cares about that issue in any meaningful way, they just vote for it because in return I vote for their tax cuts even though I'd really prefer 2000 dollar checks in perpetuity. The reason people stick around is there's meaningful balance, however if the balance goes out of whack and the party became solely about anti-abortion at the expense of the fiscal responsibility, why would a fiscal responsibility person stick around?
This is what happened to British Labour in the late 70s where the party started becoming solely about radical socialism (which was anti-Europe), and a number of high profile pro-Europe members left to form their own party, or more recently a number of pro-Europe Tories defecting to join the successor to said party.
In defense of OP though, there are plenty of Labour politicians who were radical socialists in 1979 who became bonafide Blairites by 1997, there are absolutely politicians who just go where the political wind blows (in the case of someone like Scarborough that could be his MSNBC paycheck).
Even if they have ideological differences with them, that's the whole point of being a party: you negotiate the stuff you disagree with but can tolerate, to get the stuff you agree about (plus one or two other things).
Otherwise, they're not the "third party". They're the fourth -- or maybe the fifth, behind the Greens. At best.
Probably because they aren't libertarians.
And perhaps also because the (few, to be sure) past models for successful emergent major parties aren't minor parties that hung around for decades without success first.