Tsai got 45% in a three horse race against the incumbent (OK, that means Blues got 55%). I think the odds were always against her. Apart from anything else, there are probably some voters who wouldn't vote for a woman (more than those who would vote for her because she is a woman). I didn't see much of the campaign so I don't really know, but she looked reasonably impressive to me. Certainly no disgrace.
Which means, do losers always resign? Not always. In Taiwan, Lian Chan didn't resign/leave the stage in 2000 and took over a year to go after 2004.
Elsewhere, it's not uncommon for American contenders to run more than once for the nomination, at least (not sure about if they get beaten in the actual election - please enlighten me). In the UK, it depends on the circumstances. In 1983, Michael Foot got a thumping, was seen as old and a loser. He was replaced by Kinnock with a long term project to reform the Labour Party, so when he made progress but still lost in 1987, he got another chance in 1992, after which he resigned. William Hague lost for the Conservatives in 2001 and went not because he lost but because he lost quite badly and was perceived as weird (the Conservative Party is more ruthless than the Labour Party). Michael Howard was always a stand in (also perceived as a bit weird), to be replaced by a new generation after 2005. Gordon Brown had been on the scene for 20 years, lost badly (in some senses) and was seen as weird.
Having said all that, leading the party and running for President seem to be more fluid in Taiwan. Perhaps it would not be surprising to see Tsai again in 4 years.











